The invention discloses a zero-input ripple inverter and a control method thereof. The main circuit topology of the zero-input ripple inverter comprises a DC power supply, an input capacitor, a primary side switching tube, an isolation transformer, a pick-off diode, a filtering capacitor, a polarity-reversal inverter bridge, an output filtering circuit, a power grid and a decoupling circuit. The control method comprises the steps that a power grid voltage sampling value is input to PLL to obtain a sine wave having the same frequency and the same phase as the power grid voltage sampling value,input voltage and current sampling values are subjected to MPPT to obtain the maximum DC input power, five modulated wave signals are obtained by means of a reference generation module and a modulatedwave generation module, and finally operation of a grid-connected inverter is controlled by means of a comparator and a logic circuit. According to the zero-input ripple inverter and the control method thereof, the decoupling circuit composed of a decoupling switching tube, a decoupling diode, a decoupling inductor and a decoupling capacitor is added to the primary side of the isolation transformer, and a transformer auxiliary winding is additionally arranged, the dual functions of input current harmonic suppression at grid-connected and DC power supply ends are effectively achieved.