An antenna system applied to a mobile terminal. The mobile terminal comprises a back shell, a main board received in the back shell, a bracket arranged between the back shell and the main board, and a metal wiring arranged on the surface of the bracket. A clearance area is arranged at one end of the main board; an orthographic projection of the metal wiring on the main board is located in the clearance area. The main board is provided with a grounding switch and a feeding point. The metal wiring comprises a body part, a first branch for generating low-frequency resonance, a second branch for generating high-frequency resonance and a third branch for generating medium-frequency resonance. The first branch, the second branch and the third branch respectively extend from the body part to two sides. The grounding switch and the feeding point are connected with the body part.