To improve micro-grid power quality and solve the problem that micro-grid controls active and reactive power by itself, the control scheme of two level source inverter of three-phase three-wire voltage system is analyzed. Then the mathematical model is constituted, the expression of reference current is deduced by instantaneous power theory, and the cascade control micro-grid inverter structure is proposed which is composed of inter and outer controllers. On one hand, the internal model control with one-order process is put forward to realize current control by adjusting alternating current of axis and axis. On the other hand, the feed forward control of internal model with two-order process is presented to achieve DC bus voltage control in the outer controller. Through simulation verification, the control strategy can be effective for active and reactive power control of micro grid inverter, also the inverter can follow grid voltage sag and self-adjust DC bus voltage. So the new strategy is provided for the study to improve power quality of micro-grid.