Abstract: The conventional droop-control strategy which is adopted generally for parallel inverter regulates the phase and the amplitude of the output voltage according to output active power and reactive power, respectively. However, active power and reactive power are related to both output amplitude and output phase for double closed-loop feedback voltage-source inverter. This paper deduces the equivalent output impedance of the inverter and discusses the quantitative relationship between active/reactive power and amplitude/phase of output voltage. Then a parallel control strategy based on synchronization bus and output amplitude regulated by the couple connection beween the output active power and the reactive power is proposed and the model of parallel system is established. Experimental results show the effectiveness of the control strategy.