In order to enhance the magnetic field strength of antenna coil in space,this paper proposes a method of double-layer antenna with two drive ports.First of all,this paper introduces each parameter which should be considered in the view of theory.Secondly,we change the parameters of the double-layer antenna,model and simulate it with the 3D electromagnetic simulation software Ansoft HFSS.Then,the influence of the coil number,the coil spacing,radius and the relative position of two coils on the double-layer antenna is researched.Finally,the simulate results show that the optimal design of double-layer antenna is found out and it is meaningful to the actual design of the antenna in medium-high frequency RFID reader systems.