diff --git a/tb/tb_sm3_pad_top.sv b/tb/tb_sm3_pad_top.sv
new file mode 100644
index 0000000..a17f159
--- /dev/null
+++ b/tb/tb_sm3_pad_top.sv
@@ -0,0 +1,74 @@
+`timescale 1ns / 1ps
+`include "./inc/sm3_cfg"
+//////////////////////////////////////////////////////////////////////////////////
+// Author:        ljgibbs / lf_gibbs@163.com
+// Create Date: 2020/07/21 
+// Design Name: sm3
+// Module Name: tb_sm3_pad_top
+// Description:
+//      SM3 填充模块 testbench
+//          测试 sm3_pad_core 
+// Dependencies: 
+//      inc/sm3_cfg.v
+// Revision:
+// Revision 0.01 - File Created
+//////////////////////////////////////////////////////////////////////////////////
+module tb_sm3_pad_top (                 
+);
+
+//reg
+reg                     clk;
+reg                     rst_n;
+
+reg [`INPT_DW1:0]       msg_inpt_d_i;
+reg [`INPT_BYTE_DW1:0]  msg_inpt_vld_byte_i;
+reg                     msg_inpt_vld_i;
+reg                     msg_inpt_lst_i;
+
+reg                     pad_otpt_ena_i;
+
+wire                    msg_inpt_rdy_o;
+wire                    pad_otpt_d_o;
+wire                    pad_otpt_lst_o;
+wire                    pad_otpt_vld_o;
+
+//uut
+sm3_pad_core U_sm3_pad_core(
+    .clk                    (clk                    ),
+    .rst_n                  (rst_n                  ),
+
+    .msg_inpt_d_i           (msg_inpt_d_i           ),
+    .msg_inpt_vld_byte_i    (msg_inpt_vld_byte_i    ),
+    .msg_inpt_vld_i         (msg_inpt_vld_i         ),
+    .msg_inpt_lst_i         (msg_inpt_lst_i         ),
+
+    .pad_otpt_ena_i         (pad_otpt_ena_i         ),
+
+    .msg_inpt_rdy_o         (msg_inpt_rdy_o         ),
+
+    .pad_otpt_d_o           (pad_otpt_d_o           ),
+    .pad_otpt_lst_o         (pad_otpt_lst_o         ),
+    .pad_otpt_vld_o         (pad_otpt_vld_o         )
+);
+
+initial begin
+    clk                     =0;
+    rst_n                   =0;
+    msg_inpt_d_i            =0;
+    msg_inpt_vld_byte_i     =0;
+    msg_inpt_vld_i          =0;
+    msg_inpt_lst_i          =0;
+    pad_otpt_ena_i;         =0;
+
+    #100;
+    rst_n                   =1;
+
+    @(posedge clk)
+
+end
+
+always #5 clk = ~clk; 
+
+
+
+endmodule
\ No newline at end of file