diff --git a/source/module_hamilt_lcao/hamilt_lcaodft/operator_lcao/operator_lcao.h b/source/module_hamilt_lcao/hamilt_lcaodft/operator_lcao/operator_lcao.h
index 7c08044b7c..c29ba87c0e 100644
--- a/source/module_hamilt_lcao/hamilt_lcaodft/operator_lcao/operator_lcao.h
+++ b/source/module_hamilt_lcao/hamilt_lcaodft/operator_lcao/operator_lcao.h
@@ -11,16 +11,19 @@ namespace hamilt {
 template <typename TK, typename TR>
 class OperatorLCAO : public Operator<TK> {
   public:
+
     OperatorLCAO(
         HS_Matrix_K<TK>* hsk_in, 
-        const std::vector<ModuleBase::Vector3<double>>& kvec_d_in,
-        HContainer<TR>* hR_in)
+        const std::vector<ModuleBase::Vector3<double>>& kvec_d_in, //! k-point vectors
+        HContainer<TR>* hR_in)  //! H(R) matrix, R is the Bravis lattice vector
         : hsk(hsk_in), kvec_d(kvec_d_in), hR(hR_in){}
+
     virtual ~OperatorLCAO()
     {
-        if (this->allocated_smatrix) {
+        if (this->allocated_smatrix) 
+        {
             delete[] this->smatrix_k;
-}
+        }
     }
 
     /* Function init(k) is used for update HR and HK ,
@@ -47,7 +50,8 @@ class OperatorLCAO : public Operator<TK> {
     Gamma_only case (TK = double), SK would not changed during one SCF loop, a template triangle matrix SK_temp is used
     for accelerating. General case (TK = std::complex<double>), only pointers of HK and SK saved in OperatorLCAO
     */
-    void matrixHk(MatrixBlock<TK>& hk_in, MatrixBlock<TK>& sk_in) {
+    void matrixHk(MatrixBlock<TK>& hk_in, MatrixBlock<TK>& sk_in) 
+    {
         this->get_hs_pointers();
 #ifdef __MPI
         hk_in = MatrixBlock<TK>{hmatrix_k,
@@ -59,8 +63,15 @@ class OperatorLCAO : public Operator<TK> {
                                (size_t)this->hsk->get_pv()->ncol,
                                this->hsk->get_pv()->desc};
 #else
-        hk_in = MatrixBlock<TK>{hmatrix_k, (size_t)this->hsk->get_pv()->nrow, (size_t)this->hsk->get_pv()->ncol, nullptr};
-        sk_in = MatrixBlock<TK>{smatrix_k, (size_t)this->hsk->get_pv()->nrow, (size_t)this->hsk->get_pv()->ncol, nullptr};
+        hk_in = MatrixBlock<TK>{hmatrix_k, 
+                                (size_t)this->hsk->get_pv()->nrow, 
+                                (size_t)this->hsk->get_pv()->ncol, 
+                                nullptr};
+        
+        sk_in = MatrixBlock<TK>{smatrix_k, 
+                                (size_t)this->hsk->get_pv()->nrow, 
+                                (size_t)this->hsk->get_pv()->ncol, 
+                                nullptr};
 #endif
     }
 
@@ -77,7 +88,7 @@ class OperatorLCAO : public Operator<TK> {
     virtual void set_HR_fixed(void*) { return; }
 
     /**
-     * @brief reset hr_done status
+     * @brief reset the status of 'hr_done' (if H(R) is calculated)
      */
     void set_hr_done(bool hr_done_in);
 
@@ -87,32 +98,33 @@ class OperatorLCAO : public Operator<TK> {
     void set_current_spin(const int current_spin_in);
 
     // protected:
-    //  Hamiltonian matrix which are calculated in OperatorLCAO
+    // Hamiltonian matrices which are calculated in OperatorLCAO
     HS_Matrix_K<TK>* hsk = nullptr;
     const std::vector<ModuleBase::Vector3<double>>& kvec_d;
 
   protected:
     bool new_e_iteration = true;
 
-    // Real space Hamiltonian pointer
+    //! Real-space Hamiltonian pointer
     hamilt::HContainer<TR>* hR = nullptr;
 
-    // current spin index
+    //! current spin index
     int current_spin = 0;
 
-    // if HR is calculated
+    //! if H(R) is calculated
     bool hr_done = false;
 
   private:
+
     void get_hs_pointers();
 
-    // there are H and S matrix for each k point in reciprocal space
-    // type double for gamma_only case, type complex<double> for multi-k-points
-    // case
+    //! there are H and S matrix for each k point in reciprocal space
+    //! 'double' type for gamma_only case, 
+    //! 'complex<double>' type for multi k-points case
     TK* hmatrix_k = nullptr;
     TK* smatrix_k = nullptr;
 
-    // only used for Gamma_only case
+    //! only used for Gamma_only case
     bool allocated_smatrix = false;
 };