The significant constraint for the applications of wireless power transfer is the low efficiency, compared to the traditional electric wired connection. In order to improve the transfer efficiency, a variety of compensation networks are proposed to reduce the reactive power transfer but parameter selection is only based on coupling coils and ignores the inverter loss. In this paper, compensation capacitor is designed and optimized to improve the efficiency of both the inverter and coupling coils. Based on the series-series resonant compensation network, the influence of resonant capacitor parameters on the efficiency of the system is analyzed. At the same time, the optimal values of capacitors are given considering super-capacitor constant current charging. Finally, the simulation results verify the analysis results.