diff --git a/deepmd/entrypoints/compress.py b/deepmd/entrypoints/compress.py
index ef65dd6a84..d8f8e3e933 100644
--- a/deepmd/entrypoints/compress.py
+++ b/deepmd/entrypoints/compress.py
@@ -102,7 +102,7 @@ def compress(
         10 * step,
         int(frequency),
     ]
-    jdata["training"]["save_ckpt"] = "model-compression/model.ckpt"
+    jdata["training"]["save_ckpt"] = os.path.join("model-compression", "model.ckpt")
     jdata = update_deepmd_input(jdata)
     jdata = normalize(jdata)