The invention relates to a mobile terminal-oriented single sign-on (SSO) authentication method and system. The method includes the following steps: installing a mobile phone side SSO agent program, and configuring a connection with an access control server; and actively calling an API interface provided by the agent by an application program to verify credibility of the application program itself, verifying user identity information, obtaining user information, and exiting. The mobile terminal-oriented SSO method and system realize SSO between different applications on the same device through a function module running on a mobile terminal device, and can identify the applications themselves, perform detailed logging about who accesses what application system at what time and in what place, thereby greatly improving security, effectively solving the problem that a user name and a password need to be input many times between operations of mobile terminal applications of a system, and means of application identity authentication and application sign-on address identification are adopted, thereby well guaranteeing credibility and security of the applications.