The invention discloses a method for identifying the dirt degree of the surface of a photovoltaic solar panel. The method comprises: (1), collecting an image of the surface of a photovoltaic solar panel; (2), identifying the image to distinguish the photovoltaic solar panel body and the surface dirt; (3), acquiring a surface dirt degree of the photovoltaic solar panel according to the identification result; and (4), determining whether the surface dirt degree of the photovoltaic solar panel is larger than a preset cleaning threshold, and if so, cleaning the surface of the photovoltaic solar panel. In addition, the invention also discloses a corresponding system. Therefore, the surface dirt degree of the photovoltaic solar panel can be identified automatically and whether the surface of the photovoltaic solar panel needs to be cleaned is determined automatically; and cleaning can be carried out when the surface dirt degree of the photovoltaic solar panel is accumulated to reach a cleaning threshold, so that the water resources are saved and the investment cost is lowered.