A roaming authentication method based on WAPI. The present invention includes the steps of adopting a terminal and a wireless access point to initiate a WAPI security mechanism, relating the terminal to the wireless access point, and initiating a WAPI authentication process and so on. And a highly safe and convenient roaming authentication method based on WAPI is provided, so as to solve the technical problem that how the specific method of certificate roaming authentication is realized, the certificate of external network authentication server can not be obtained to establish a trustful relationship, and the terminal perhaps can not realize roaming authentication.