A login method performed by a service apparatus and an identity management apparatus, the service apparatus being a client side provided by a service party and including a computer program installed on a terminal device and the identity management apparatus comprising a first server side deployed on a server configured by an identity management party, wherein the identity management apparatus is configured to manage a registered primary account and at least one sub-account associated for at least the service apparatus with the registered primary account, wherein the registered primary account is bound to identity document information of a corresponding user, an identification of the registered primary account is associated with the identity document information of the corresponding user, and the registered primary account comprises an identification information set comprising a plurality of pieces of identification information bound to the registered primary account, the method comprising: after a login process of the service apparatus to log in to a second server side of an Internet service is triggered, acquiring, by an interface module in the service apparatus, verification information of a target primary account, and sending the verification information to the identity management apparatus, wherein the verification information comprises an identification of the target primary account and at least one piece of identification information, and the at least one piece of identification information comprised in the verification information is determined based on a security level required by the service apparatus for the login process; after receiving the verification information by the identity management apparatus, performing, by the identity management apparatus, identity verification on the target primary account by using the identification information set of the registered primary account; after the identity verification is passed, acquiring login information of the at least one sub-account associated for the service apparatus in advance with the target primary account and sending the login information to the interface module; and after the interface module receives the login information, determining, by the service apparatus, a target sub-account among the at least one sub-account and logging in to the second server side using the corresponding acquired login information of the target sub-account. after a login process of the service apparatus to log in to a second server side of an Internet service is triggered, acquiring, by an interface module in the service apparatus, verification information of a target primary account, and sending the verification information to the identity management apparatus, wherein the verification information comprises an identification of the target primary account and at least one piece of identification information, and the at least one piece of identification information comprised in the verification information is determined based on a security level required by the service apparatus for the login process; after receiving the verification information by the identity management apparatus, performing, by the identity management apparatus, identity verification on the target primary account by using the identification information set of the registered primary account; after the identity verification is passed, acquiring login information of the at least one sub-account associated for the service apparatus in advance with the target primary account and sending the login information to the interface module; and after the interface module receives the login information, determining, by the service apparatus, a target sub-account among the at least one sub-account and logging in to the second server side using the corresponding acquired login information of the target sub-account.