The invention relates to a photovoltaic module cleaning method. The method comprises steps: 1) related data for decisive factors influencing whether the photovoltaic module is cleaned or not are acquired, the data are processed, and accurate values of the decisive factors which are a generation gain level, a sediment transport rate, a precipitation amount and a module masking rate influencing whether the photovoltaic module is cleaned or not are obtained; 2) the accurate values of the generation gain level, the sediment transport rate, and the precipitation amount obtained in the first step are fed to a first-stage fuzzy controller for processing, and an initial cleaning index, that is, the initial cleaning probability of the photovoltaic module, is obtained; and 3) the accurate value of the module masking rate obtained in the first step and the initial cleaning index obtained in the second step are fed to a second-stage fuzzy controller for processing, and a cleaning decisive index is obtained. Thus, a decisive data support is provided for cleaning of the photovoltaic module, the defect that the original photovoltaic module cleaning decision subjective consciousness is strong is broken, and thus, cleaning and maintenance of the photovoltaic power station module are more scientific.