The invention discloses an assembling method of an interface. The interface comprises a metal base and a connection terminal. An insert-connection cavity is defined in the metal base. The connection terminal is arranged in the insert-connection cavity and comprises multiple metal terminals and a glue base, and the glue base surrounds the metal terminals to divide each metal terminal into an insert-connection part and a pin part. The assembling method includes the following steps that the connection terminal is inserted into the insert-connection cavity from the front end of the insert-connection cavity, and the pin parts of the metal terminals stretch out of the insert-connection cavity; waterproof glue is injected into the portion between the outer peripheral wall of the glue base and the inner peripheral wall of the insert-connection cavity; part of the rear end of the metal base is bent to abut against the rear end face of the glue base. According to the assembling method of the interface, the connection terminal can be conveniently connected with an external plug and an electronic device in the mobile terminal. The waterproof performance of the interface can be improved, and therefore the working reliability of the interface is improved.