An account login method, wherein the method comprises: obtaining, by a set top box, a terminal identifier of a mobile terminal by using a wireless network, wherein both the set top box and the mobile terminal access the wireless network; searching, by the set top box according to the terminal identifier, a relationship table for a service account and a password that are corresponding to the terminal identifier, wherein the relationship table comprises a correspondence between a terminal identifier and each of a service account and a password; and if the set top box finds the service account and the password that are corresponding to the terminal identifier, logging in to, by the set top box, a content server by using the service account and the password that are corresponding to the terminal identifier, characterized in that the terminal identifier is an account of an application A being used by the mobile terminal, and the relationship table comprises a correspondence between the account of the application A and each of a service account and a password; the obtaining, by a set top box, a terminal identifier of a mobile terminal by using a wireless network comprises: sending, by the set top box, an authentication request of the application A to the mobile terminal by using the wireless network, wherein the authentication request of the application A is used to instruct the mobile terminal to send, to the set top box, the account of the application A being used by the mobile terminal; and the searching, by the set top box according to the terminal identifier, a relationship table for a service account and a password that are corresponding to the terminal identifier comprises: searching, by the set top box according to the account of the application A being used by the mobile terminal, the relationship table for a service account and a password that are corresponding to the account of the application A being used by the mobile terminal. obtaining, by a set top box, a terminal identifier of a mobile terminal by using a wireless network, wherein both the set top box and the mobile terminal access the wireless network; searching, by the set top box according to the terminal identifier, a relationship table for a service account and a password that are corresponding to the terminal identifier, wherein the relationship table comprises a correspondence between a terminal identifier and each of a service account and a password; and if the set top box finds the service account and the password that are corresponding to the terminal identifier, logging in to, by the set top box, a content server by using the service account and the password that are corresponding to the terminal identifier, characterized in that the terminal identifier is an account of an application A being used by the mobile terminal, and the relationship table comprises a correspondence between the account of the application A and each of a service account and a password; the obtaining, by a set top box, a terminal identifier of a mobile terminal by using a wireless network comprises: sending, by the set top box, an authentication request of the application A to the mobile terminal by using the wireless network, wherein the authentication request of the application A is used to instruct the mobile terminal to send, to the set top box, the account of the application A being used by the mobile terminal; and the searching, by the set top box according to the terminal identifier, a relationship table for a service account and a password that are corresponding to the terminal identifier comprises: searching, by the set top box according to the account of the application A being used by the mobile terminal, the relationship table for a service account and a password that are corresponding to the account of the application A being used by the mobile terminal. sending, by the set top box, an authentication request of the application A to the mobile terminal by using the wireless network, wherein the authentication request of the application A is used to instruct the mobile terminal to send, to the set top box, the account of the application A being used by the mobile terminal; and the searching, by the set top box according to the terminal identifier, a relationship table for a service account and a password that are corresponding to the terminal identifier comprises: searching, by the set top box according to the account of the application A being used by the mobile terminal, the relationship table for a service account and a password that are corresponding to the account of the application A being used by the mobile terminal.