Abstract: In order to solve the problem of current distortion in the case of cascaded photovoltaic inverter with unbalanced power between units, an optimized control strategy for cascaded photovoltaic inverters based on reactive power compensation is proposed in this paper. The stable operating range of the inverter under the unit power factor is studied in the dq coordinate system. Thereby, the reactive current value to be compensated when the power is unbalanced is obtained. The active power of each unit is distributed proportionally, and the reactive power is distributed according to the affordability. Through quantitative analysis, the degree that the reactive power compensation method affects the voltage loop is obtained, and the system control block diagram is optimized so as to eliminate this influence. Simulations and experiments verify the effectiveness and feasibility of the proposed control strategy. The results show that when the photovoltaic power is severely unbalanced, the proposed method can still be used to ensure the inverter to run stably and the system voltage loop is no longer affected by reactive power compensation. The research can provide references for the control of the photovoltaic inverters.