IPSec is the only security technology that can be used pervasively in the Internet. Through analyzing the process of IPSec, we point out that network security processor is the key component to implement IPSec protocol efficiently. The architecture and application of the security processor state-of-arts are introduced in detail. Because the processing power of the network security processor of the shelf can not satisfy the requirement of the ports with OC-48 speed or higher,the analysis and forecast of the next generation network security processor architecture is given at the end of the paper.