Abstract: For the problem that output power of a single inverter in wireless power transmission system could not satisfy large power requirement, power combination mechanics of wireless power transmission system based on multi inverters was researched. An equivalent circuit model of wireless power transmission system was built which was based on power combination topology of two inverters, and laws of output power and transfer efficiency of the system were obtained. The research results are as following. Output power and transfer efficiency of the system are shared by each branch inverter, and distributed in each branch complementarily because of different power driving ability of each branch. System characteristics of wireless power transmission system based on power combination of multi inverters is identical with that of the system based on single inverter.