The invention relates to an identification joint method and comprises user terminal login service provider equipment which sends a redirection request to the user terminal, wherein, the redirection request carries identification management equipment address information, a service provider mark and user identification information; the user terminal connects the identification management equipment and sends the service provider mark and the user identification information to the identification management equipment according to the redirection request; and the identification management equipment preserves the mapping relationship among the login identification of the user terminal login identification management equipment, the user identification information and the service provider mark. The invention realizes the establishment of the mapping relationship between the user identification on a plurality of SPs and the identification on the identification management equipment; by using the mapping relationship, when the user logins the identification management equipment or a SP and then accesses other SPs, the identification management equipment can inquire and obtain the identification information of the user on other SPs, thereby realizing united login.