This paper analyzes and researches the theories of the encryption communications and identities authentication over the Internet banking based on the PKI technology. Combined with the specific Internet banking system, this research tries to design Internet banking system communication encryption and identities verification and the workflow and main functions. Implementing application to enhance confidentiality of the information transferred by the network communication, this research solves the problems of encrypting Internet banking data and verifying the identities of users and Internet banking. Finally, this paper explores the key technology more in-depth in the designing.