In the wireless power transfer (WPT)system, the received power of the load is sensitive to the change of mutual inductance and resistance.When there is deviation between the receiving coil and the transmitting coil or the change of load equivalent impedance, the received power of the load should be basically stable through effective control.Based on the analysis of the WPT system with DC/DC circuit in the secondary side, the relationship between mutual inductance and load voltage and current, as well as the relationship between duty cycle of DC/DC circuit and load power are given.The stable control strategy of output power by detecting load voltage and current and then adjusting DC/DC circuit is proposed.Finally, through Matlab/Simulink simulation and the establishment of the experimental platform, the paper verifies the effectiveness and correctness of the theoretical analysis and control strategy in this paper.