This paper researches a power decoupling micro-inverter for photovoltaic power generation. The micro-inverters is composed of the basic buck-boost circuit and the current source from the high-frequency inverter circuit in parallel. Decoupling capacitors are connected in series between the two circuits. It uses peak current control to make the voltage of decoupling capacitor double terminals boost and the ripple increase, decreases decoupling capacitance, and avoids low-lifetime electrolytic condenser so as to prolong inverter's service life. Five working states of the circuit are analyzed. The corresponding circuit parameters and peak current control strategy are designed. Circuit simulation model is built and tested by using PSIM software. Simulation results show that the proposed topology and its control strategy can reduce the decoupling capacitors’ capacitance and prolong the service life of micro-inverter. This work is supported by National Natural Science Foundation of China (No. 51467006) and Science and Technology Industrial Planning Project of Jiangxi Province (No. 20151BBE50118 and No. 20161BBH80032).