In the design of wireless power transfer system, multiple transmitters can be added to the system to improve the power transmission capacity of the system and reduce the voltage and current stress on the power conversion components. A dual-transmitter wireless power transfer system is proposed in this paper, which includes two operating modes: standby operation mode and strengthening operation mode. When the power required by the receiver is relatively low, one transmitter will work in the standby operation mode, and only the other transmitter provides power for the receiver to reduce the system loss; When the power required by the receiver is relatively high, the transmitter will switch from standby operation mode to strengthening operation mode, and provide power for the receiver together with another transmitter. In addition, aiming at the energy cancellation problem caused by the inconsistent output voltage phases of the two transmitter inverters, this paper proposes a synchronization control method to keep them synchronized to improve the power capacity of the system. Finally, the feasibility and effectiveness of the proposed method are verified by experiments.