The invention discloses a platform authentication method suitable for trusted network connect (TNC) architecture based on tri-element peer authentication (TePA). The method relates to a platform authentication protocol of tri-element peer authentication, and the protocol improves network security as compared with prior platform authentication protocols; in the platform authentication protocol of the TNC architecture based on TePA, a policy manager plays a role as a trusted third party, which is convenient for concentrated management, thus enhancing manageability; the invention relates to the platform authentication protocol of the TNC architecture based on TePA, has different implementation methods and is beneficial for different dispositions and realizations.