Abstract: Provided is a system for authenticating a user based on a lock screen and a method thereof, and more particularly, to a system for authenticating a user and a method thereof, which operates a user terminal even in a locked state of the user terminal in order to perform user authentication more easily. A system for authenticating a user based on a lock screen may include a push server receiving identification information of a user who accesses an authentication request server and identification information of the authentication request server and generating a push message based on the identification information and transmitting the push message to the user terminal corresponding to the identification information of the user.