diff --git a/YD_Event.Application/Event/UnifiedRegistrationService.cs b/YD_Event.Application/Event/UnifiedRegistrationService.cs
index 302cfc9..f6015d2 100644
--- a/YD_Event.Application/Event/UnifiedRegistrationService.cs
+++ b/YD_Event.Application/Event/UnifiedRegistrationService.cs
@@ -717,31 +717,55 @@ public class UnifiedRegistrationService : ITransient
     /// </summary>
     private static RegistrationValidationResult? ValidatePersonAges(List<UnifiedPersonInput> persons, EventProjectGroup group, bool isTeamProject, RegistrationValidationResult result)
     {
-        // 检查是否有超过最大年龄限制的队员
-        var aboveAgePerson = persons.FirstOrDefault(p => p.BirthDate > group.BirthDateEnd);
-        if (aboveAgePerson != null)
+        // 组别未配置年龄限制时，跳过年龄检查（避免 DateTime.MinValue 造成的误判）
+        bool hasEndLimit = group.BirthDateEnd != DateTime.MinValue;
+        bool hasStartLimit = group.BirthDateStart != DateTime.MinValue;
+
+        // ① 检查是否有超过最大年龄限制的队员（出生日期晚于 BirthDateEnd → 太小）
+        if (hasEndLimit)
         {
-            result.IsValid = false;
-            result.ErrorMessage = $"队员{aboveAgePerson.Name}的年龄超过组别最大限制。要求出生日期不晚于：{group.BirthDateEnd:yyyy-MM-dd}，实际：{aboveAgePerson.BirthDate:yyyy-MM-dd}";
-            result.Details.Add(CreateValidationDetail("年龄验证", false, result.ErrorMessage));
-            return result;
+            var aboveAgePerson = persons.FirstOrDefault(p => p.BirthDate > group.BirthDateEnd);
+            if (aboveAgePerson != null)
+            {
+                result.IsValid = false;
+                result.ErrorMessage = $"队员{aboveAgePerson.Name}的年龄低于组别最小年龄要求。要求出生日期不晚于：{group.BirthDateEnd:yyyy-MM-dd}，实际：{aboveAgePerson.BirthDate:yyyy-MM-dd}";
+                result.Details.Add(CreateValidationDetail("年龄验证", false, result.ErrorMessage));
+                return result;
+            }
         }
 
-        // 统计年龄状态
-        var inTargetCount = persons.Count(p => p.BirthDate >= group.BirthDateStart && p.BirthDate <= group.BirthDateEnd);
-        var belowTargetCount = persons.Count(p => p.BirthDate < group.BirthDateStart);
-        bool hasBelow = belowTargetCount > 0;
-        bool allBelow = belowTargetCount == persons.Count;
-
-        // 团队项目跨组验证
-        if (isTeamProject && hasBelow && inTargetCount == 0)
+        // ② 检查是否有年龄超过最小年龄限制的队员（出生日期早于 BirthDateStart → 超龄 / 年龄太大）
+        if (hasStartLimit)
         {
-            string errorMessage = allBelow 
+            var belowAgePerson = persons.FirstOrDefault(p => p.BirthDate < group.BirthDateStart);
+            if (belowAgePerson != null)
+            {
+                result.IsValid = false;
+                result.ErrorMessage = $"队员{belowAgePerson.Name}的年龄超过组别最大年龄限制。要求出生日期不早于：{group.BirthDateStart:yyyy-MM-dd}，实际：{belowAgePerson.BirthDate:yyyy-MM-dd}";
+                result.Details.Add(CreateValidationDetail("年龄验证", false, result.ErrorMessage));
+                return result;
+            }
+        }
+
+        // ③ 统计年龄状态（仅用于详情展示）
+        int inTargetCount = 0;
+        int belowTargetCount = 0;
+        if (hasStartLimit && hasEndLimit)
+        {
+            inTargetCount = persons.Count(p => p.BirthDate >= group.BirthDateStart && p.BirthDate <= group.BirthDateEnd);
+            belowTargetCount = persons.Count(p => p.BirthDate < group.BirthDateStart);
+        }
+
+        // 团队项目跨组验证（仅当配置了年龄区间时才需要）：保留原有业务规则——团队中至少需要有一名成员属于目标年龄段
+        if (hasStartLimit && hasEndLimit && isTeamProject && belowTargetCount > 0 && inTargetCount == 0)
+        {
+            bool allBelow = belowTargetCount == persons.Count;
+            string errorMessage = allBelow
                 ? "跨组报名时，团队中所有成员年龄均小于目标年龄段，团队中至少需要有一名成员属于目标年龄段"
                 : "跨组报名时，团队中至少需要有一名成员属于目标年龄段";
-            
-            string itemName = allBelow 
-                ? "年龄跨组验证（全部小于目标年龄）" 
+
+            string itemName = allBelow
+                ? "年龄跨组验证（全部小于目标年龄）"
                 : "年龄跨组验证";
 
             result.IsValid = false;
@@ -751,9 +775,12 @@ public class UnifiedRegistrationService : ITransient
         }
 
         // 添加验证通过的详情
-        result.Details.Add(hasBelow 
-            ? CreateValidationDetail("年龄跨组", true, "符合年龄跨组报名要求")
-            : CreateValidationDetail("年龄验证", true, "所有队员均在目标年龄段内"));
+        if (hasStartLimit || hasEndLimit)
+        {
+            result.Details.Add(belowTargetCount > 0
+                ? CreateValidationDetail("年龄跨组", true, "符合年龄跨组报名要求")
+                : CreateValidationDetail("年龄验证", true, "所有队员均在目标年龄段内"));
+        }
 
         return null;
     }