diff --git a/csst_ifs_gehong/spec1d.py b/csst_ifs_gehong/spec1d.py
index 83f42985c5dcecb518a8af35b53575e1d7411fc7..dbcea4f3b10722212ab953a89a981628fb2228ab 100644
--- a/csst_ifs_gehong/spec1d.py
+++ b/csst_ifs_gehong/spec1d.py
@@ -1120,10 +1120,15 @@ class SingleStar():
             print("Notice: Your input magnitude (mag) is > 26 mag or < 8 mag.")
         if (teff < 2820) or (teff > 20129):
             print("Notice: Your input effective tempreture (teff) is beyond the range of stellar template [2820, 20129], which will be automatically adjusted to the upper/lower limit.")
-        if (feh > 0.81) or (feh < -2.69):
+            if (teff < 2820):
+                teff = 2820
+            if (teff > 20129):
+                teff = 20129
+        if (feh > 0.81):
             print("Notice: Your input metallicity (feh) is beyond the range of stellar template [-2.69, 0.81], which will be automatically adjusted to the upper limit.")
-        #if (feh < -2.69):
-        #    raise Exception('Your input metallicity (feh) is beyond the range of stellar template [-2.69, 0.81]')
+            feh = 0.81
+        if (feh < -2.69):
+            raise Exception('Your input metallicity (feh) is beyond the range of stellar template [-2.69, 0.81]')
         
     
         StarTemp = template.templates