diff --git a/csst_mci_sim/csst_mci_sim.py b/csst_mci_sim/csst_mci_sim.py
index e6e135afdb5b80765ef58327ba1d486f4f3d22b6..b95bbc94c2005b00c957e9df3d5f951d08b65123 100644
--- a/csst_mci_sim/csst_mci_sim.py
+++ b/csst_mci_sim/csst_mci_sim.py
@@ -1715,7 +1715,7 @@ class MCIsimulator():
         ############ load star data catlog #####################            
         ##starcat='selection_20230517_concat.csv'
         
-        starcat='GaiaSource_675688-675713'
+        starcat='GaiaSource_675688-675713.csv'
              
         self.log.info('Stat catlog file name is %s' % (starcat))