A grid-connected inverter based on a digital phase-locked loop technology comprises an external power grid and is characterized in that the grid-connected inverter comprises a wind power generating set, a photovoltaic array, a control unit, an energy storage unit and a grid-connected inverter body. The working method of the grid-connected inverter comprises the steps of collection, processing, controlling and output. The grid-connected inverter based on the digital phase-locked loop technology and the working method thereof have the advantages that the control algorithm is advanced, and control precision and stability are good; computation is high in speed, the structure is simple, and control is easy; the problems such as zero drift, component saturation and demands for initial calibration can be solved by being matched with a DSP and a PLL; the upper limit working frequency of the PLL is improved, and the PLL technology is made to be more flexible.