diff --git a/source/module_esolver/esolver_sdft_pw.cpp b/source/module_esolver/esolver_sdft_pw.cpp
index 3d6831847df..cc7356991cb 100644
--- a/source/module_esolver/esolver_sdft_pw.cpp
+++ b/source/module_esolver/esolver_sdft_pw.cpp
@@ -97,6 +97,18 @@ void ESolver_SDFT_PW::eachiterfinish(int iter)
 }
 void ESolver_SDFT_PW::afterscf(const int istep)
 {
+    // save charge difference into files for charge extrapolation
+    if (GlobalV::CALCULATION != "scf")
+    {
+        this->CE.save_files(istep,
+                            GlobalC::ucell,
+#ifdef __MPI
+                            this->pw_big,
+#endif
+                            this->pelec->charge,
+                            &this->sf);
+    }
+
     if(GlobalV::out_chg > 0)
     {
 	    for(int is=0; is<GlobalV::NSPIN; is++)
diff --git a/tests/integrate/183_PW_MD_SDFT_10S/result.ref b/tests/integrate/183_PW_MD_SDFT_10S/result.ref
index 2c5e10acfdd..b038ed62f2d 100644
--- a/tests/integrate/183_PW_MD_SDFT_10S/result.ref
+++ b/tests/integrate/183_PW_MD_SDFT_10S/result.ref
@@ -1,5 +1,5 @@
-etotref -325.9620844050852
-etotperatomref -162.9810422025
-totalforceref 5.845306
-totalstressref 2118.104645
-totaltimeref +6.6991
\ No newline at end of file
+etotref -325.9634101970396
+etotperatomref -162.9817050985
+totalforceref 5.935670
+totalstressref 2117.931975
+totaltimeref +1.7343
diff --git a/tests/integrate/183_PW_MD_SDFT_5D10S/result.ref b/tests/integrate/183_PW_MD_SDFT_5D10S/result.ref
index 7fb52d9816d..bf74442d388 100644
--- a/tests/integrate/183_PW_MD_SDFT_5D10S/result.ref
+++ b/tests/integrate/183_PW_MD_SDFT_5D10S/result.ref
@@ -1,5 +1,5 @@
-etotref -321.3106144709864
-etotperatomref -160.6553072355
-totalforceref 4.231022
-totalstressref 2049.873553
-totaltimeref +5.7928
+etotref -321.3172324016796
+etotperatomref -160.6586162008
+totalforceref 4.252426
+totalstressref 2050.529177
+totaltimeref +1.5023
diff --git a/tests/integrate/183_PW_MD_SDFT_ALL/result.ref b/tests/integrate/183_PW_MD_SDFT_ALL/result.ref
index 2668cb64a6c..d48635e2166 100644
--- a/tests/integrate/183_PW_MD_SDFT_ALL/result.ref
+++ b/tests/integrate/183_PW_MD_SDFT_ALL/result.ref
@@ -1,5 +1,5 @@
-etotref -227.9076422621504
-etotperatomref -113.9538211311
-totalforceref 0.506056
-totalstressref 42595.617093
-totaltimeref +5.1337
+etotref -227.9095962344375
+etotperatomref -113.9547981172
+totalforceref 0.486750
+totalstressref 42594.627201
+totaltimeref +4.4362