diff --git a/deepmd/pt/model/network/mlp.py b/deepmd/pt/model/network/mlp.py
index 2b8383806b..582abf4d69 100644
--- a/deepmd/pt/model/network/mlp.py
+++ b/deepmd/pt/model/network/mlp.py
@@ -32,6 +32,7 @@
 )
 from deepmd.pt.utils.env import (
     DEFAULT_PRECISION,
+    DP_DTYPE_PROMOTION_STRICT,
     PRECISION_DICT,
 )
 from deepmd.pt.utils.utils import (
@@ -200,6 +201,8 @@ def forward(
             The output.
         """
         ori_prec = xx.dtype
+        if not DP_DTYPE_PROMOTION_STRICT:
+            xx = xx.to(self.prec)
         yy = (
             torch.matmul(xx, self.matrix) + self.bias
             if self.bias is not None
@@ -214,6 +217,8 @@ def forward(
                 yy += torch.concat([xx, xx], dim=-1)
             else:
                 yy = yy
+        if not DP_DTYPE_PROMOTION_STRICT:
+            yy = yy.to(ori_prec)
         return yy
 
     def serialize(self) -> dict:
diff --git a/deepmd/pt/utils/env.py b/deepmd/pt/utils/env.py
index 3ee0b7b54d..81dce669ff 100644
--- a/deepmd/pt/utils/env.py
+++ b/deepmd/pt/utils/env.py
@@ -15,6 +15,7 @@
 )
 
 SAMPLER_RECORD = os.environ.get("SAMPLER_RECORD", False)
+DP_DTYPE_PROMOTION_STRICT = os.environ.get("DP_DTYPE_PROMOTION_STRICT", "0") == "1"
 try:
     # only linux
     ncpus = len(os.sched_getaffinity(0))