Among all the restraints of the development of E-commerce, the security problem of transaction has become the key element. Meanwhile all kinds of E-commerce security technologies have attracted more and more attention and study. In order to find better solutions of E-commerce security problems, such as anti-wiretapping, anti-juggling of the information, transaction denying, and the false order form or contract and so on. According to the ISO Open Systems interconnect seven layer protocol models, the E-commerce security system can be divided into five layers that network service layer, encryption technology layer, secure authentication layer, security protocol layer and application layer. Based on these five layers, make an instruction and analysis of the current technology used most in E-commerce security area, such as Firewall technology, encryption technology, authentication technology as well as security protocol; and then put forward some suggestions.