With the development of Internet, there are more and more applications around us are connected tightly with it. Security of network is important. This thesis will follow OSI 7-layers architecture, which defined by ISO, to propose several hardware improvement approaches of network security. In data-link layer, we improve performance of CRC calculation with parallel CRC calculation, such that a 32-bit data can be finished using CRC calculation in one cycle. In network layer and transport layer, bit-oriented instruction set has good performance for processing packet header. In application, we implement DES and AES algorithm in hardware. We integrate all hardware module with ARM7TDMI coprocessor¡¦s interface. Finally, we download integrated circuit into Xilinx XCV2000E chip to observe its demo to verify it.