The invention discloses a sign-in method based on a two-dimensional code. The sign-in method based on the two-dimensional code is characterized by comprising the following steps of: displaying the two-dimensional code; scanning the two-dimensional code by a mobile terminal, analysing to obtain the access point information, sign-in server information and user identifier information of the two-dimensional code, connecting to a WIFI (wireless fidelity) network according to the access point information, connecting to a sign-in server according to the sign-in server information, and sending the user identifier information to the sign-in server by the mobile terminal; and confirming the sign-in of a user by the sign-in server according to the received user identifier information, and recording the sign-in time of the user according to a scanning time. With the adoption of the sign-in method based on the two-dimensional code disclosed by the invention, no-queuing sign-in can be realized, and the case of copying the two-dimensional code for allograph can be prevented. Simultaneously, the invention further discloses a mobile terminal and a sign-in server.