diff --git a/docs/advanced/input_files/input-main.md b/docs/advanced/input_files/input-main.md
index 2c83ed749d..d7250f7f33 100644
--- a/docs/advanced/input_files/input-main.md
+++ b/docs/advanced/input_files/input-main.md
@@ -118,7 +118,7 @@
     - [cal\_force](#cal_force)
     - [force\_thr](#force_thr)
     - [force\_thr\_ev](#force_thr_ev)
-    - [force\_thr\_ev2](#force_thr_ev2)
+    - [force\_zero\_out](#force_zero_out)
     - [relax\_bfgs\_w1](#relax_bfgs_w1)
     - [relax\_bfgs\_w2](#relax_bfgs_w2)
     - [relax\_bfgs\_rmax](#relax_bfgs_rmax)
@@ -1507,10 +1507,10 @@ These variables are used to control the geometry relaxation.
 - **Default**: 0.0257112
 - **Unit**: eV/Angstrom (0.03889 Ry/Bohr)
 
-### force_thr_ev2
+### force_zero_out
 
 - **Type**: Real
-- **Description**: The calculated force will be set to 0 when it is smaller than the parameter `force_thr_ev2`.
+- **Description**: The force whose value is smaller than `force_zero_out` will be treated as zero.
 - **Default**: 0.0
 - **Unit**: eV/Angstrom
 
diff --git a/source/module_io/input_conv.cpp b/source/module_io/input_conv.cpp
index 00d7491d36..b6ceaff1bd 100644
--- a/source/module_io/input_conv.cpp
+++ b/source/module_io/input_conv.cpp
@@ -177,8 +177,8 @@ void Input_Conv::Convert()
 
 
 #ifdef __LCAO
-    Force_Stress_LCAO<double>::force_invalid_threshold_ev = PARAM.inp.force_thr_ev2;
-    Force_Stress_LCAO<std::complex<double>>::force_invalid_threshold_ev = PARAM.inp.force_thr_ev2;
+    Force_Stress_LCAO<double>::force_invalid_threshold_ev = PARAM.inp.force_zero_out;
+    Force_Stress_LCAO<std::complex<double>>::force_invalid_threshold_ev = PARAM.inp.force_zero_out;
 #endif
 
     BFGS_Basic::relax_bfgs_w1 = PARAM.inp.relax_bfgs_w1;
diff --git a/source/module_io/read_input_item_relax.cpp b/source/module_io/read_input_item_relax.cpp
index 80c012b6ff..cc0efa2464 100644
--- a/source/module_io/read_input_item_relax.cpp
+++ b/source/module_io/read_input_item_relax.cpp
@@ -109,9 +109,9 @@ void ReadInput::item_relax()
         this->add_item(item);
     }
     {
-        Input_Item item("force_thr_ev2");
+        Input_Item item("force_zero_out");
         item.annotation = "force invalid threshold, unit: eV/Angstrom";
-        read_sync_double(input.force_thr_ev2);
+        read_sync_double(input.force_zero_out);
         this->add_item(item);
     }
     {
diff --git a/source/module_io/test/read_input_ptest.cpp b/source/module_io/test/read_input_ptest.cpp
index 2ec4bdce1d..058c895376 100644
--- a/source/module_io/test/read_input_ptest.cpp
+++ b/source/module_io/test/read_input_ptest.cpp
@@ -107,7 +107,7 @@ TEST_F(InputParaTest, ParaRead)
     EXPECT_TRUE(param.inp.symmetry_autoclose);
     EXPECT_EQ(param.inp.cal_force, 0);
     EXPECT_NEAR(param.inp.force_thr, 1.0e-3, 1.0e-7);
-    EXPECT_DOUBLE_EQ(param.inp.force_thr_ev2, 0);
+    EXPECT_DOUBLE_EQ(param.inp.force_zero_out, 0);
     EXPECT_DOUBLE_EQ(param.inp.stress_thr, 1.0e-2);
     EXPECT_DOUBLE_EQ(param.inp.press1, 0.0);
     EXPECT_DOUBLE_EQ(param.inp.press2, 0.0);
diff --git a/source/module_io/test/support/INPUT b/source/module_io/test/support/INPUT
index b6d31ba51a..d366d5b0db 100644
--- a/source/module_io/test/support/INPUT
+++ b/source/module_io/test/support/INPUT
@@ -102,7 +102,7 @@ relax_nmax                     1 #number of ion iteration steps
 out_stru                       0 #output the structure files after each ion step
 force_thr                      0.001 #force threshold, unit: Ry/Bohr
 force_thr_ev                   0.0257112 #force threshold, unit: eV/Angstrom
-force_thr_ev2                  0 #force invalid threshold, unit: eV/Angstrom
+force_zero_out                 0 #force invalid threshold, unit: eV/Angstrom
 relax_cg_thr                   0.5 #threshold for switching from cg to bfgs, unit: eV/Angstrom
 stress_thr                     0.01 #stress threshold
 press1                         0 #target pressure, unit: KBar
diff --git a/source/module_parameter/input_parameter.h b/source/module_parameter/input_parameter.h
index 548e7da575..ad918356cc 100644
--- a/source/module_parameter/input_parameter.h
+++ b/source/module_parameter/input_parameter.h
@@ -157,7 +157,7 @@ struct Input_para
     double relax_cg_thr = 0.5; ///< threshold when cg to bfgs, pengfei add 2011-08-15
     double force_thr = -1;     ///< threshold of force in unit (Ry/Bohr)
     double force_thr_ev = -1;  ///< threshold of force in unit (eV/Angstrom)
-    double force_thr_ev2 = 0;  ///< invalid force threshold, mohan add 2011-04-17
+    double force_zero_out = 0;  ///< invalid force threshold, mohan add 2011-04-17
     double stress_thr = 0.5;   ///< Pengfei Li 2017-11-01 ///<LiuXh update 20180515
     double press1 = 0;
     double press2 = 0;