A method for measuring the density of dust accumulation on photovoltaic panels based on scattered light intensity is proposed to solve the problems of existing methods for detecting the degree of dust accumulation on photovoltaic panels,which have difficulties in directly measuring the transmittance of photovoltaic panels and high interference from ambient light.Modulated light is used in this method to investigate the spatial distribution of scattered light intensity on the surface of dust accumulation photovoltaic panels based on the principle of angle-resolved scattering (ARS) measurement.According to the distribution law of scattered light intensity,the relationship between scattered light intensity and dust density of photovoltaic panels in a specific stereo angle range is established.The experimental results show that the linearity of the system is better when the detector is placed on the same side of the light source.The scattered light intensity increases linearly with the increase of the dust accumulation density of the photovoltaic panel, and then the growth slows down gradually and finally tends to a certain value.This method has good resistance to ambient light interference and can reflect the dust accumulation state of photovoltaic panels intuitively.