diff --git a/backend/src/main/java/com/designhub/entity/TaskItem.java b/backend/src/main/java/com/designhub/entity/TaskItem.java
index ec1365c..233d647 100644
--- a/backend/src/main/java/com/designhub/entity/TaskItem.java
+++ b/backend/src/main/java/com/designhub/entity/TaskItem.java
@@ -66,6 +66,11 @@ public class TaskItem implements Serializable {
      */
     private BigDecimal estimatedHours;
 
+    /**
+     * 截止时间（接单时计算）
+     */
+    private LocalDateTime deadline;
+
     /**
      * 接单人ID
      */
diff --git a/backend/src/main/java/com/designhub/mapper/TaskItemMapper.java b/backend/src/main/java/com/designhub/mapper/TaskItemMapper.java
index 6a2a616..d9de69f 100644
--- a/backend/src/main/java/com/designhub/mapper/TaskItemMapper.java
+++ b/backend/src/main/java/com/designhub/mapper/TaskItemMapper.java
@@ -268,6 +268,7 @@ public interface TaskItemMapper extends BaseMapper<TaskItem> {
             "receiver_name = #{receiverName}, " +
             "receiver_dept_id = #{receiverDeptId}, " +
             "status = 'in_progress', " +
+            "deadline = CASE WHEN #{deadline} IS NOT NULL THEN #{deadline} ELSE deadline END, " +
             "update_time = NOW() " +
             "WHERE id = #{itemId} " +
             "AND status = 'pending' " +
@@ -276,7 +277,8 @@ public interface TaskItemMapper extends BaseMapper<TaskItem> {
     int grabItem(@Param("itemId") Long itemId,
                  @Param("receiverId") Long receiverId,
                  @Param("receiverName") String receiverName,
-                 @Param("receiverDeptId") Long receiverDeptId);
+                 @Param("receiverDeptId") Long receiverDeptId,
+                 @Param("deadline") LocalDateTime deadline);
 
     /**
      * 解锁子任务
diff --git a/backend/src/main/java/com/designhub/service/TaskItemService.java b/backend/src/main/java/com/designhub/service/TaskItemService.java
index 101a638..2983ef4 100644
--- a/backend/src/main/java/com/designhub/service/TaskItemService.java
+++ b/backend/src/main/java/com/designhub/service/TaskItemService.java
@@ -272,8 +272,17 @@ public class TaskItemService {
             throw new BusinessException(ResultCode.TASK_ALREADY_TAKEN, "该子任务已被接单");
         }
 
-        // 乐观锁抢单（同时设置接单部门ID）
-        int result = taskItemMapper.grabItem(itemId, userId, user.getRealName(), user.getDeptId());
+        // 计算deadline
+        LocalDateTime now = LocalDateTime.now();
+        LocalDateTime deadline = null;
+        if (item.getEstimatedHours() != null && item.getEstimatedHours().compareTo(java.math.BigDecimal.ZERO) > 0) {
+            deadline = workHoursCalculator.calculateDeadline(now, item.getEstimatedHours());
+            log.info("子任务deadline已计算：从接单时间 {} 开始，预估 {} 小时，截止时间 {}",
+                    now, item.getEstimatedHours(), deadline);
+        }
+
+        // 乐观锁抢单（同时设置接单部门ID和deadline）
+        int result = taskItemMapper.grabItem(itemId, userId, user.getRealName(), user.getDeptId(), deadline);
         if (result == 0) {
             throw new BusinessException(ResultCode.TASK_ALREADY_TAKEN, "抢单失败，该子任务可能已被他人接单");
         }
diff --git a/backend/src/main/resources/db/migration/V13__add_task_item_deadline.sql b/backend/src/main/resources/db/migration/V13__add_task_item_deadline.sql
new file mode 100644
index 0000000..b03a63d
--- /dev/null
+++ b/backend/src/main/resources/db/migration/V13__add_task_item_deadline.sql
@@ -0,0 +1,5 @@
+-- V13__add_task_item_deadline.sql
+
+-- 添加子任务截止时间字段
+ALTER TABLE `task_item`
+    ADD COLUMN `deadline` DATETIME NULL COMMENT '截止时间（接单时计算）' AFTER `estimated_hours`;
diff --git a/frontend/src/api/task.ts b/frontend/src/api/task.ts
index 06974ce..a9e9f06 100644
--- a/frontend/src/api/task.ts
+++ b/frontend/src/api/task.ts
@@ -85,6 +85,7 @@ export interface TaskItem {
   unitScore: number
   totalScore: number
   estimatedHours?: number
+  deadline?: string  // 截止时间（接单时计算）
   receiverId?: number
   receiverName?: string
   status: string  // locked/pending/in_progress/completed/rejected
diff --git a/frontend/src/components/TaskCard.vue b/frontend/src/components/TaskCard.vue
index dd9e112..897e986 100644
--- a/frontend/src/components/TaskCard.vue
+++ b/frontend/src/components/TaskCard.vue
@@ -167,6 +167,7 @@ interface TaskItem {
   status: string
   createTime?: string
   estimatedHours?: number
+  deadline?: string  // 截止时间（接单时计算）
 }
 
 interface Task {
@@ -340,18 +341,15 @@ const getSubTaskStatusClass = (status: string) => {
   return classMap[status] || ''
 }
 
-// 计算子任务完成截止日期（从接单开始计算+预计完成需要的时间）
+// 获取子任务完成截止日期（使用后端返回的deadline字段）
 // 只有已接单或进行中的子任务才显示截止时间
 const getSubTaskDeadline = (subTask: TaskItem) => {
   // 只有进行中或已完成的子任务才显示截止时间
   if (subTask.status !== 'in_progress' && subTask.status !== 'completed') return null
-  if (!subTask.createTime || !subTask.estimatedHours) return null
-  // 从创建时间（接单时间）开始计算
-  const startTime = dayjs(subTask.createTime)
-  // 计算截止时间：创建时间 + 预计工时
-  const deadline = startTime.add(subTask.estimatedHours, 'hour')
-  // 格式化为"XX月XX日XX时"
-  return deadline.format('MM月DD日HH时')
+  // 直接使用后端返回的deadline字段
+  if (!subTask.deadline) return null
+  // 格式化为"XX月XX日HH时"
+  return dayjs(subTask.deadline).format('MM月DD日HH时')
 }
 </script>
 
diff --git a/frontend/src/views/CreateTask.vue b/frontend/src/views/CreateTask.vue
index 3afb034..41121c5 100644
--- a/frontend/src/views/CreateTask.vue
+++ b/frontend/src/views/CreateTask.vue
@@ -988,21 +988,16 @@ const estimatedTotalHours = computed(() => {
   return totalHours
 })
 
-// 格式化时效显示
+// 格式化时效显示（基于工作时间配置）
 const formattedEstimatedTime = computed(() => {
   const hours = estimatedTotalHours.value
   if (hours === 0) return '--'
   
   if (hours < 1) {
     return `${Math.round(hours * 60)}分钟`
-  } else if (hours < 24) {
-    const h = Math.floor(hours)
-    const m = Math.round((hours - h) * 60)
-    return m > 0 ? `${h}小时${m}分钟` : `${h}小时`
   } else {
-    const days = Math.floor(hours / 24)
-    const remainHours = Math.round(hours % 24)
-    return remainHours > 0 ? `${days}天${remainHours}小时` : `${days}天`
+    // 使用formatWorkHours函数来格式化（基于工作时间配置）
+    return formatWorkHours(hours)
   }
 })
 
diff --git a/frontend/src/views/TaskHall.vue b/frontend/src/views/TaskHall.vue
index c3f6886..9fda124 100644
--- a/frontend/src/views/TaskHall.vue
+++ b/frontend/src/views/TaskHall.vue
@@ -2913,18 +2913,15 @@ const getSubTaskStatusText = (status: string | undefined) => {
   return statusMap[status || ''] || status || '未知'
 }
 
-// 计算子任务完成截止日期（从接单开始计算+预计完成需要的时间）
+// 获取子任务完成截止日期（使用后端返回的deadline字段）
 // 只有已接单或进行中的子任务才显示截止时间
 const getSubTaskDeadline = (subTask: any) => {
   // 只有进行中或已完成的子任务才显示截止时间
   if (subTask.status !== 'in_progress' && subTask.status !== 'completed') return null
-  if (!subTask.createTime || !subTask.estimatedHours) return null
-  // 从创建时间（接单时间）开始计算
-  const startTime = dayjs(subTask.createTime)
-  // 计算截止时间：创建时间 + 预计工时
-  const deadline = startTime.add(subTask.estimatedHours, 'hour')
+  // 直接使用后端返回的deadline字段
+  if (!subTask.deadline) return null
   // 格式化为"XX月XX日HH时"
-  return deadline.format('MM月DD日HH时')
+  return dayjs(subTask.deadline).format('MM月DD日HH时')
 }
 
 // 展开/折叠任务子任务详情