diff --git a/query/query_parser.py b/query/query_parser.py
index 6435aa5..b3aa3d0 100644
--- a/query/query_parser.py
+++ b/query/query_parser.py
@@ -151,6 +151,17 @@ class QueryParser:
         """Return pre-initialized translator."""
         return self._translator
 
+    @staticmethod
+    def _pick_query_translation_model(source_lang: str, target_lang: str) -> str:
+        """Pick the translation capability for query-time translation."""
+        src = str(source_lang or "").strip().lower()
+        tgt = str(target_lang or "").strip().lower()
+        if src == "zh" and tgt == "en":
+            return "opus-mt-zh-en"
+        if src == "en" and tgt == "zh":
+            return "opus-mt-en-zh"
+        return "deepl"
+
     def _simple_tokenize(self, text: str) -> List[str]:
         """
         Lightweight tokenizer fallback.
@@ -303,21 +314,31 @@ class QueryParser:
                             thread_name_prefix="query-translation-wait",
                         )
                         for lang in target_langs:
+                            model_name = self._pick_query_translation_model(detected_lang, lang)
+                            log_debug(
+                                f"Submitting query translation | source={detected_lang} target={lang} model={model_name}"
+                            )
                             translation_futures[lang] = translation_executor.submit(
                                 self.translator.translate,
                                 query_text,
                                 lang,
                                 detected_lang,
                                 "ecommerce_search_query",
+                                model_name,
                             )
                     else:
                         for lang in target_langs:
+                            model_name = self._pick_query_translation_model(detected_lang, lang)
+                            log_debug(
+                                f"Submitting query translation | source={detected_lang} target={lang} model={model_name}"
+                            )
                             self._translation_executor.submit(
                                 self.translator.translate,
                                 query_text,
                                 lang,
                                 detected_lang,
                                 "ecommerce_search_query",
+                                model_name,
                             )
 
                     if translations:
--
libgit2 0.21.2