diff --git a/jeecg-boot-platform/jeecg-boot-module-bpm-flowable/src/main/java/org/jeecg/modules/extbpm/process/common/expression/FlowNodeExpression.java b/jeecg-boot-platform/jeecg-boot-module-bpm-flowable/src/main/java/org/jeecg/modules/extbpm/process/common/expression/FlowNodeExpression.java
index fce908a..26f11b9 100644
--- a/jeecg-boot-platform/jeecg-boot-module-bpm-flowable/src/main/java/org/jeecg/modules/extbpm/process/common/expression/FlowNodeExpression.java
+++ b/jeecg-boot-platform/jeecg-boot-module-bpm-flowable/src/main/java/org/jeecg/modules/extbpm/process/common/expression/FlowNodeExpression.java
@@ -6,6 +6,7 @@ import com.alibaba.fastjson.JSONObject;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang.StringUtils;
+import org.jeecg.common.exception.JeecgBootException;
 import org.flowable.engine.RuntimeService;
 import org.flowable.engine.delegate.DelegateExecution;
 import org.flowable.engine.runtime.Execution;
@@ -276,6 +277,28 @@ public class FlowNodeExpression {
         return sysbase.getUserByRoleIdLocalApi(roleId);
     }
 
+    /**
+     * Get required usernames for a Flowable multi-instance task.
+     * An empty collection would otherwise make Flowable skip the task, so fail fast instead.
+     * Example: ${flowNodeExpression.getRequiredUsersListByRole('roleIdValue')}
+     *
+     * @param roleId system role id
+     * @return non-empty username list
+     */
+    public List<String> getRequiredUsersListByRole(String roleId) {
+        if (StringUtils.isBlank(roleId)) {
+            throw new JeecgBootException("流程角色ID不能为空");
+        }
+
+        List<String> usernames = ISysBaseAPI.getUsernamesByRoleIdLocalApi(roleId);
+        log.info("流程多实例按角色取人，roleId={}, usernames={}, count={}", roleId, usernames,
+                usernames == null ? 0 : usernames.size());
+        if (CollectionUtils.isEmpty(usernames)) {
+            throw new JeecgBootException("角色[" + roleId + "]未配置有效用户，流程无法继续");
+        }
+        return usernames;
+    }
+
     /**
      * Get subprocess variable.
      * Example: ${flowNodeExpression.getSonProcessVariable(execution, 'subApproveUser')}
diff --git a/jeecg-module-system/jeecg-system-api/jeecg-system-cloud-api/src/main/java/org/jeecg/common/system/api/fallback/SysBaseAPIFallback.java b/jeecg-module-system/jeecg-system-api/jeecg-system-cloud-api/src/main/java/org/jeecg/common/system/api/fallback/SysBaseAPIFallback.java
index 7b8a3d3..9336d11 100644
--- a/jeecg-module-system/jeecg-system-api/jeecg-system-cloud-api/src/main/java/org/jeecg/common/system/api/fallback/SysBaseAPIFallback.java
+++ b/jeecg-module-system/jeecg-system-api/jeecg-system-cloud-api/src/main/java/org/jeecg/common/system/api/fallback/SysBaseAPIFallback.java
@@ -10,6 +10,7 @@ import org.jeecg.common.constant.enums.EmailTemplateEnum;
 import org.jeecg.common.system.api.ISysBaseAPI;
 import org.jeecg.common.system.vo.*;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -24,6 +25,12 @@ public class SysBaseAPIFallback implements ISysBaseAPI {
     @Setter
     private Throwable cause;
 
+    @Override
+    public List<String> getUsernamesByRoleIdLocalApi(String roleId) {
+        log.error("Query usernames by role failed, roleId={}", roleId, cause);
+        return Collections.emptyList();
+    }
+
     @Override
     public void sendSysAnnouncement(MessageDTO message) {
         log.error("发送消息失败 {}", cause);
diff --git a/jeecg-module-system/jeecg-system-api/jeecg-system-local-api/src/main/java/org/jeecg/common/system/api/ISysBaseAPI.java b/jeecg-module-system/jeecg-system-api/jeecg-system-local-api/src/main/java/org/jeecg/common/system/api/ISysBaseAPI.java
index 632c7c4..8a994ba 100644
--- a/jeecg-module-system/jeecg-system-api/jeecg-system-local-api/src/main/java/org/jeecg/common/system/api/ISysBaseAPI.java
+++ b/jeecg-module-system/jeecg-system-api/jeecg-system-local-api/src/main/java/org/jeecg/common/system/api/ISysBaseAPI.java
@@ -575,4 +575,13 @@ public interface ISysBaseAPI extends CommonAPI {
     List<String> getUsersListByDeptIdAndRoleIdLocalApi(String deptId, String roleId);
 
     List<String> getUserByRoleIdLocalApi(String roleId);
- }
+
+    /**
+     * Query active usernames by role for Flowable multi-instance tasks.
+     * This method intentionally uses an independent query path so existing role queries remain unchanged.
+     *
+     * @param roleId system role id
+     * @return active username list
+     */
+    List<String> getUsernamesByRoleIdLocalApi(String roleId);
+}
diff --git a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/SysUserMapper.java b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/SysUserMapper.java
index 4a359dc..dfe3411 100644
--- a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/SysUserMapper.java
+++ b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/SysUserMapper.java
@@ -251,4 +251,13 @@ public interface SysUserMapper extends BaseMapper<SysUser> {
 	 * @return
 	 */
 	List<SysUser> getUserByRoleId(String roleId);
+
+	/**
+	 * Query active usernames by role through a dedicated statement.
+	 * It must not reuse the overloaded getUserByRoleId statement used by the user management page.
+	 *
+	 * @param roleId role id
+	 * @return username list
+	 */
+	List<String> getUsernamesByRoleId(@Param("roleId") String roleId);
 }
diff --git a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/xml/SysUserMapper.xml b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/xml/SysUserMapper.xml
index 4efa813..248441f 100644
--- a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/xml/SysUserMapper.xml
+++ b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/mapper/xml/SysUserMapper.xml
@@ -59,6 +59,17 @@
 		</if>
 	</select>
 
+	<!-- Multi-instance flow task query. Keep it separate from the overloaded getUserByRoleId statement. -->
+	<select id="getUsernamesByRoleId" resultType="java.lang.String">
+		select distinct u.username
+		from sys_user u
+		inner join sys_user_role ur on ur.user_id = u.id
+		where u.del_flag = 0
+		  and ur.role_id = #{roleId}
+		  and u.username is not null
+		  and u.username != ''
+	</select>
+
 	<select id="getUserByRoleIdWithDeptIds" resultType="org.jeecg.modules.system.vo.SysUserRoleDeptsVo">
 		SELECT
 		u.id as user_id,
diff --git a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/ISysUserService.java b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/ISysUserService.java
index bcdeaa9..99c06f9 100644
--- a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/ISysUserService.java
+++ b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/ISysUserService.java
@@ -498,4 +498,13 @@ public interface ISysUserService extends IService<SysUser> {
 	List<String> queryUserByDeptAndROle(@NotBlank(message = "deptId不为空") String deptId, @NotBlank(message = "角色id不为空") String roleId, @NotBlank(message = "secretLevel不为空") Integer secretLevel);
 
 	List<String> getUserByRoleId(String roleId);
+
+	/**
+	 * Query active usernames by role for Flowable multi-instance task assignment.
+	 * This is separate from the legacy role-user query to avoid changing its behavior.
+	 *
+	 * @param roleId system role id
+	 * @return active username list
+	 */
+	List<String> getUsernamesByRoleId(String roleId);
 }
diff --git a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysBaseApiImpl.java b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysBaseApiImpl.java
index 34baa00..7d0de64 100644
--- a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysBaseApiImpl.java
+++ b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysBaseApiImpl.java
@@ -2161,4 +2161,15 @@ public class SysBaseApiImpl implements ISysBaseAPI {
 				.stream()
 				.collect(Collectors.toList());
 	}
-}
\ No newline at end of file
+
+	@Override
+	public List<String> getUsernamesByRoleIdLocalApi(String roleId) {
+		List<String> usernames = sysUserService.getUsernamesByRoleId(roleId);
+		return Optional.ofNullable(usernames)
+				.orElse(Collections.emptyList())
+				.stream()
+				.filter(StringUtils::isNotBlank)
+				.distinct()
+				.collect(Collectors.toList());
+	}
+}
diff --git a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysUserServiceImpl.java b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysUserServiceImpl.java
index 8bed5db..56a329c 100644
--- a/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysUserServiceImpl.java
+++ b/jeecg-module-system/jeecg-system-biz/src/main/java/org/jeecg/modules/system/service/impl/SysUserServiceImpl.java
@@ -2424,4 +2424,12 @@ public class SysUserServiceImpl extends ServiceImpl<SysUserMapper, SysUser> impl
 	public List<String> getUserByRoleId(String roleId){
 		return sysUserMapper.getUserByRoleId(roleId).stream().map(SysUser::getUsername).collect(Collectors.toList()) ;
 	}
+
+	@Override
+	public List<String> getUsernamesByRoleId(String roleId) {
+		if (StringUtils.isBlank(roleId)) {
+			return Collections.emptyList();
+		}
+		return sysUserMapper.getUsernamesByRoleId(roleId);
+	}
 }