Abstract: Snow is a common weather phenomenon, but snow on insulators will affect its electrical performance. In this paper, snow volume conductivity is measured to find factors which have impacts on it and snow flashover process is simulated on the rectangle plate model. The results show that snow volume conductivity reach maximum in the vicinity of the melting point and the increase of density and snow water conductivity will lead to the increase of conductivity. Snow flashover process is close related to water content, the increase of water content, density and snow water conductivity will lead to the decrease of snow flashover voltage.