diff --git a/backend/app/api/simulation.py b/backend/app/api/simulation.py
index 3a8e1e3f..342557cf 100644
--- a/backend/app/api/simulation.py
+++ b/backend/app/api/simulation.py
@@ -20,6 +20,29 @@ from ..models.project import ProjectManager
 logger = get_logger('mirofish.api.simulation')
 
 
+def _get_default_platform(simulation_id: str) -> str:
+    """
+    根据模拟配置返回默认平台
+
+    读取 SimulationState 中的 enable_twitter / enable_reddit 设置，
+    返回该模拟实际使用的平台，而非硬编码 'reddit'。
+
+    Args:
+        simulation_id: 模拟ID
+
+    Returns:
+        'twitter' 或 'reddit'
+    """
+    try:
+        manager = SimulationManager()
+        state = manager._load_simulation_state(simulation_id)
+        if state:
+            return state.get_default_platform()
+    except Exception:
+        pass
+    return "reddit"
+
+
 # Interview prompt 优化前缀
 # 添加此前缀可以避免Agent调用工具，直接用文本回复
 INTERVIEW_PROMPT_PREFIX = "结合你的人设、所有的过往记忆与行动，不调用任何工具直接用文本回复我："
@@ -996,8 +1019,8 @@ def get_simulation_profiles(simulation_id: str):
         platform: 平台类型（reddit/twitter，默认reddit）
     """
     try:
-        platform = request.args.get('platform', 'reddit')
-        
+        platform = request.args.get('platform') or _get_default_platform(simulation_id)
+
         manager = SimulationManager()
         profiles = manager.get_profiles(simulation_id, platform=platform)
         
@@ -1058,8 +1081,8 @@ def get_simulation_profiles_realtime(simulation_id: str):
     from datetime import datetime
     
     try:
-        platform = request.args.get('platform', 'reddit')
-        
+        platform = request.args.get('platform') or _get_default_platform(simulation_id)
+
         # 获取模拟目录
         sim_dir = os.path.join(Config.OASIS_SIMULATION_DATA_DIR, simulation_id)
         
@@ -1997,15 +2020,15 @@ def get_simulation_posts(simulation_id: str):
     返回帖子列表（从SQLite数据库读取）
     """
     try:
-        platform = request.args.get('platform', 'reddit')
+        platform = request.args.get('platform') or _get_default_platform(simulation_id)
         limit = request.args.get('limit', 50, type=int)
         offset = request.args.get('offset', 0, type=int)
-        
+
         sim_dir = os.path.join(
             os.path.dirname(__file__),
             f'../../uploads/simulations/{simulation_id}'
         )
-        
+
         db_file = f"{platform}_simulation.db"
         db_path = os.path.join(sim_dir, db_file)
         
@@ -2065,24 +2088,26 @@ def get_simulation_posts(simulation_id: str):
 @simulation_bp.route('/<simulation_id>/comments', methods=['GET'])
 def get_simulation_comments(simulation_id: str):
     """
-    获取模拟中的评论（仅Reddit）
-    
+    获取模拟中的评论
+
     Query参数：
+        platform: 平台类型（twitter/reddit，根据模拟配置自动选择）
         post_id: 过滤帖子ID（可选）
         limit: 返回数量
         offset: 偏移量
     """
     try:
+        platform = request.args.get('platform') or _get_default_platform(simulation_id)
         post_id = request.args.get('post_id')
         limit = request.args.get('limit', 50, type=int)
         offset = request.args.get('offset', 0, type=int)
-        
+
         sim_dir = os.path.join(
             os.path.dirname(__file__),
             f'../../uploads/simulations/{simulation_id}'
         )
         
-        db_path = os.path.join(sim_dir, "reddit_simulation.db")
+        db_path = os.path.join(sim_dir, f"{platform}_simulation.db")
         
         if not os.path.exists(db_path):
             return jsonify({
diff --git a/backend/app/services/simulation_manager.py b/backend/app/services/simulation_manager.py
index 0d161a90..bda876cd 100644
--- a/backend/app/services/simulation_manager.py
+++ b/backend/app/services/simulation_manager.py
@@ -97,6 +97,15 @@ class SimulationState:
             "error": self.error,
         }
     
+    def get_default_platform(self) -> str:
+        """根据启用状态返回默认平台"""
+        if self.enable_twitter and self.enable_reddit:
+            return "reddit"  # 两者都启用时保持原默认
+        elif self.enable_twitter:
+            return "twitter"
+        else:
+            return "reddit"
+
     def to_simple_dict(self) -> Dict[str, Any]:
         """简化状态字典（API返回使用）"""
         return {
@@ -478,12 +487,15 @@ class SimulationManager:
         
         return simulations
     
-    def get_profiles(self, simulation_id: str, platform: str = "reddit") -> List[Dict[str, Any]]:
+    def get_profiles(self, simulation_id: str, platform: str = None) -> List[Dict[str, Any]]:
         """获取模拟的Agent Profile"""
         state = self._load_simulation_state(simulation_id)
         if not state:
             raise ValueError(f"模拟不存在: {simulation_id}")
-        
+
+        if platform is None:
+            platform = state.get_default_platform()
+
         sim_dir = self._get_simulation_dir(simulation_id)
         profile_path = os.path.join(sim_dir, f"{platform}_profiles.json")
         
diff --git a/frontend/src/api/simulation.js b/frontend/src/api/simulation.js
index f878586f..4dddd073 100644
--- a/frontend/src/api/simulation.js
+++ b/frontend/src/api/simulation.js
@@ -35,19 +35,21 @@ export const getSimulation = (simulationId) => {
 /**
  * 获取模拟的 Agent Profiles
  * @param {string} simulationId
- * @param {string} platform - 'reddit' | 'twitter'
+ * @param {string} [platform] - 'reddit' | 'twitter'（省略时由后端根据模拟配置自动选择）
  */
-export const getSimulationProfiles = (simulationId, platform = 'reddit') => {
-  return service.get(`/api/simulation/${simulationId}/profiles`, { params: { platform } })
+export const getSimulationProfiles = (simulationId, platform) => {
+  const params = platform ? { platform } : {}
+  return service.get(`/api/simulation/${simulationId}/profiles`, { params })
 }
 
 /**
  * 实时获取生成中的 Agent Profiles
  * @param {string} simulationId
- * @param {string} platform - 'reddit' | 'twitter'
+ * @param {string} [platform] - 'reddit' | 'twitter'（省略时由后端根据模拟配置自动选择）
  */
-export const getSimulationProfilesRealtime = (simulationId, platform = 'reddit') => {
-  return service.get(`/api/simulation/${simulationId}/profiles/realtime`, { params: { platform } })
+export const getSimulationProfilesRealtime = (simulationId, platform) => {
+  const params = platform ? { platform } : {}
+  return service.get(`/api/simulation/${simulationId}/profiles/realtime`, { params })
 }
 
 /**
@@ -111,14 +113,14 @@ export const getRunStatusDetail = (simulationId) => {
 /**
  * 获取模拟中的帖子
  * @param {string} simulationId
- * @param {string} platform - 'reddit' | 'twitter'
+ * @param {string} [platform] - 'reddit' | 'twitter'（省略时由后端根据模拟配置自动选择）
  * @param {number} limit - 返回数量
  * @param {number} offset - 偏移量
  */
-export const getSimulationPosts = (simulationId, platform = 'reddit', limit = 50, offset = 0) => {
-  return service.get(`/api/simulation/${simulationId}/posts`, {
-    params: { platform, limit, offset }
-  })
+export const getSimulationPosts = (simulationId, platform, limit = 50, offset = 0) => {
+  const params = { limit, offset }
+  if (platform) params.platform = platform
+  return service.get(`/api/simulation/${simulationId}/posts`, { params })
 }
 
 /**
diff --git a/frontend/src/components/Step2EnvSetup.vue b/frontend/src/components/Step2EnvSetup.vue
index a27ba347..3a962de8 100644
--- a/frontend/src/components/Step2EnvSetup.vue
+++ b/frontend/src/components/Step2EnvSetup.vue
@@ -912,7 +912,7 @@ const fetchProfilesRealtime = async () => {
   if (!props.simulationId) return
   
   try {
-    const res = await getSimulationProfilesRealtime(props.simulationId, 'reddit')
+    const res = await getSimulationProfilesRealtime(props.simulationId)
     
     if (res.success && res.data) {
       const prevCount = profiles.value.length
diff --git a/frontend/src/components/Step5Interaction.vue b/frontend/src/components/Step5Interaction.vue
index 9eb791a1..bb0d5484 100644
--- a/frontend/src/components/Step5Interaction.vue
+++ b/frontend/src/components/Step5Interaction.vue
@@ -918,7 +918,7 @@ const loadProfiles = async () => {
   if (!props.simulationId) return
   
   try {
-    const res = await getSimulationProfilesRealtime(props.simulationId, 'reddit')
+    const res = await getSimulationProfilesRealtime(props.simulationId)
     if (res.success && res.data) {
       profiles.value = res.data.profiles || []
       addLog(t('log.loadedProfiles', { count: profiles.value.length }))