In view of constant improvement and powerful destructive force of network attack technology and more and more important role of Internet in people's life, how to protect Internet from destruction and interference of attacks has become an important task concerning the security and availability of Internet. This paper designs the software of a hardware detection system, which is mainly composed of network port module, data packet receiving statistics module, data packet sending statistics module, PCI module and upper software module. The hardware part of the whole detection system is described by Verilog HDL language and finally it is realized on FPGA.