The invention discloses a coordinated control method and device of photovoltaic optimizers and a photovoltaic inverter applied to a photovoltaic grid-connected system. The photovoltaic grid-connected system comprises N blocks of photovoltaic modules, N photovoltaic optimizers and the photovoltaic inverter, wherein N is greater than or equal to 1; each photovoltaic module is independently connected to an input side of one photovoltaic optimizer; and output sides of the N photovoltaic optimizers are connected to a DC side of the photovoltaic inverter. The coordinated control method comprises the steps of determining an operating parameter of the photovoltaic grid-connected system, wherein the size of the operating parameter can reflect the overall conversion efficiency of the photovoltaic grid-connected system; judging whether the operating parameter is smaller than a preset value or not; and if so, adjusting DC side voltage of the photovoltaic inverter until the operating parameter is not smaller than the preset value. By the coordinated control method and device, the overall conversion efficiency of the photovoltaic grid-connected system is improved.