The invention relates to a photovoltaic MPPT (Maximum Power Point Tracking) method based on an improved grey wolf optimization algorithm. According to the technical scheme, the method comprises the steps: S1, selecting N random values from [0, 1] to serve as the initial position of a grey wolf population, wherein grey wolf individuals represent the duty ratio in a photovoltaic system; S2, acquiring the output power of the photovoltaic system under the control of each duty ratio, taking the output power as the fitness of gray wolf individuals, and recording the three gray wolves with the maximum fitness as alpha wolf, beta wolf and delta wolf in sequence; S3, shrinking the search range of the grey wolf population, and updating the upper and lower limits of a search interval; S4, performing position updating on the grey wolf population by using an improved position updating formula; S5, executing reverse search, comparing with gray wolf population fitness, and updating alpha wolf, beta wolf and delta wolf; S6, judging whether a termination condition is met or not, and if yes, stopping iteration and stabilizing the photovoltaic system at the duty ratio corresponding to the alpha wolf; otherwise, returning to the step S2, and continuing iteration.