The invention discloses a proportional integral quasi-resonance control method for a photovoltaic power generation system in a direct-current microgrid, belongs to the technical field of transformation of electrical energy, and aims to solve the problem of low system efficiency because the periodic fluctuation of direct-current bus voltage in the direct-current microgrid makes the photovoltaic power generation system cannot be continuously located in the highest power point. The method comprises the process as follows: the given value of current of a photovoltaic battery is set; the current of the photovoltaic battery is acquired, and is difference from the given value thereof to be respectively input in a proportional integral controller and a quasi-resonance controller; the summation between the output value of the proportional integral controller and the output value of the quasi-resonance controller is used as the duty ratio of a boosting circuit in the photovoltaic power generation system; and the control signal of a power switching device in the boosting circuit is obtained by the duty ratio through a pulse width modulation circuit to realize the control to the current of the photovoltaic battery. The method of the invention is used for controlling the photovoltaic power generation system in the direct-current microgrid.