A method for processing a registration exception in a user registration procedure is provided to solve the problem that network devices are unable to determine subsequent handling procedures when a registration exception occurs in a registration, where it is impossible to distinguish the initial registration and the re-registration according to whether the registration request is a protected register. According to the solution disclosed by the embodiments of the present invention, after the I-CSCF forwards the registration request to the S-CSCF and determines that a registration exception occurs, the I-CSCF returns a registration failure message to the terminal initiating the registration request or reselects a new S-CSCF, according to instruction information, indicating whether the registration request is an initial registration or a re-registration, carried in the registration request or according to S-CSCF-associated information carried in a response from the HSS.