To solve the problem of voltage distortion and unbalance caused by non-linear and unbalanced load, several inverters connected in parallel to micro-grid bus are used to control the bus quality. Taking a single inverter as an example, the causes of the output voltage quality degradation caused by the nonlinear unbalanced mixed load are analyzed. A master-slave control strategy is proposed, in which the master inverter acts as the voltage source and the slave inverter acts as the current source. The remaining available capacity of the slave inverter is used to compensate the harmonic and negative sequence current of the load, while the fundamental current and zero sequence current of the load are shared by the master-slave inverter. The control strategy effectively reduces the distortion rate and unbalance degree of the output voltage of the inverter, and embeds the power quality control function into the slave inverter, which avoids adding additional power quality control devices and reduces the system cost. Finally, the effectiveness and feasibility of the proposed control strategy are verified by building a simulation model in PSCAD environment.