The stability control of bus voltage is the premise which guarantees the two-stage photovoltaic inverter to operate continuously and in a stable condition. Currently, increasing the capacitance of the partial capacitor and adding a parallel power resistance are common ways in the midpoint potential balance control of single-phase inverter. However, none of them can completely eliminate the issue of bus capacitance deviation. Besides, it makes the circuit more complicated and reduces the efficiency of the system. A novel method for stability control of the bus voltage by adjusting the amplitude of the grid-connected current is presented. In this method, both the high-end and the low-end bus voltage are sampled respectively, the sampling error is the difference between the measured value and the expected value, then the error is sent to the control circuit. The bus voltage control algorithm, called dual-loop control, is implemented by respective controller so that the voltage reaches a steady state and is compared with single-loop control. Many targeted tests have been performed on the 3 kW half-bridge grid-connected photovoltaic inverter based on this algorithm. Experimental results demonstrate that the proposed control strategy is accurate and feasible for two-stage photovoltaic grid-connected inverter.