The invention discloses a photovoltaic grid-connected inverter active support control method based on a standard three-order model of a synchronous generator. The method comprises the steps of: performing modeling according to a rotor motion equation and a transient voltage equation of a synchronous generator; and simulating an excitation link and a speed regulation link of the synchronous generator to solve the problems of small inertia and small damping of a power system, wherein the control strategy enables the photovoltaic grid-connected inverter to have the external characteristics of a synchronous generator, the control structure gets rid of a PLL phase-locked loop used for photovoltaic grid connection, grid-connected inverter control does not change depending on network frequency changes, and the autonomy and disturbance rejection of inverter control are improved. The Boost converter achieves MPPT control and simultaneously completes unit power factor sine wave voltage stabilitycontrol of the grid-side inverter; the photovoltaic grid-connected inverter plays a role in stabilizing and supporting the frequency, and the exciter gets rid of the effect of a reactive feedback loop arranged according to the reactive-voltage droop characteristic on voltage adjustment, plays a role in stabilizing and supporting the voltage, and improves the photovoltaic grid-connected stability.