The development of internet brings people unprecedented freedom and convenience. Nevertheless, it also leads to conflicts between behavior of individual and the legitimate rights of society. The internet real-name system is just an effective means to compensate for this defect. The internet real-name system has played an important role in promoting orderly development of internet environment by declaring his real identity. This paper designs an internet real-name authentication system based on PKI. The system makes full use of digital certificate issued by the third-party authority organization, and their implied relationship of public and private key pairs, then exerts a strict background verification mechanism to ensure the real identity of internet registered users. The internet real-name authentication system based on PKI provides a reliable solution to internet real-name system.