diff --git a/server-rs/crates/api-server/src/tripo3d/storage.rs b/server-rs/crates/api-server/src/tripo3d/storage.rs
index 98393d8a4..efafde061 100644
--- a/server-rs/crates/api-server/src/tripo3d/storage.rs
+++ b/server-rs/crates/api-server/src/tripo3d/storage.rs
@@ -156,6 +156,12 @@ pub(crate) async fn store_model3d_artifact(
         )
         .await
         .map_err(|error| map_oss_error(error, "aliyun-oss"))?;
+    // HEAD 复核回来的 Content-Type 才是落库与对外共用的那份：只把本地解析值给调用方，
+    // 会出现「接口返回的 content type」与「asset_object.content_type」不一致。
+    let effective_content_type = head
+        .content_type
+        .clone()
+        .unwrap_or_else(|| content_type.clone());
     let now_micros = current_utc_micros();
     // asset_object 的 ID 必须是 (owner, operation_kind, operation_id, slot) 的稳定派生值，
     // 否则 SpacetimeDB 侧会以“生成结果 asset object ID 不是 operation 稳定 ID”拒绝整笔提交。
@@ -169,7 +175,7 @@ pub(crate) async fn store_model3d_artifact(
         head.bucket,
         head.object_key.clone(),
         AssetObjectAccessPolicy::Private,
-        head.content_type.or(Some(content_type.clone())),
+        Some(effective_content_type.clone()),
         head.content_length,
         Some(sha256.clone()),
         MODEL3D_ASSET_KIND.to_string(),
@@ -182,7 +188,7 @@ pub(crate) async fn store_model3d_artifact(
     .map_err(map_editor_asset_field_error)?;
     Ok(StoredModel3dArtifact {
         object_key: head.object_key,
-        content_type,
+        content_type: effective_content_type,
         content_length: head.content_length,
         sha256,
         asset_object,