diff --git a/ObservationSim/PSF/PSFInterp.py b/ObservationSim/PSF/PSFInterp.py
index 058acca032f174f0dcaf36d75f7f146937e7e29d..60dbf267eb4cddca0bed4cf35a2d9dd6181bc3fb 100644
--- a/ObservationSim/PSF/PSFInterp.py
+++ b/ObservationSim/PSF/PSFInterp.py
@@ -305,7 +305,19 @@ class PSFInterp(PSFModel):
             if bandpass.blue_limit < bandwave and bandwave < bandpass.red_limit:
                 return twave
         return -1
- 
+    def _findWave_sencondary(self, bandpass):
+        w_dist = np.zeros(self.nwave)
+        for twave in range(self.nwave):
+            bandwave = self.PSF_data[twave][0]['wavelength']
+            d1 = bandwave - bandpass.blue_limit
+            d2 = bandwave - bandpass.red_limit
+            if d1 * d2 <= 0:
+                w_dist[twave] = 0
+            else:
+                w_dist[twave] = np.min([abs(d1), abs(d2)])
+        
+        minTwawe = np.where(w_dist == np.min(w_dist))
+        return minTwawe[0][0]
 
     def get_PSF(self, chip, pos_img, bandpass, galsimGSObject=True, findNeighMode='treeFind', folding_threshold=5.e-3, pointing_pa=0.0):
         """
@@ -325,8 +337,7 @@ class PSFInterp(PSFModel):
         assert self.iccd == int(chip.getChipLabel(chipID=chip.chipID)), 'ERROR: self.iccd != chip.chipID'
         twave = self._findWave(bandpass)
         if twave == -1:
-            print("!!!PSF bandpass does not match.")
-            exit()
+            twave = self._findWave_sencondary(bandpass)
         PSFMat = self.psfMat[twave]
         cen_col= self.cen_col[twave]
         cen_row= self.cen_row[twave]