Abstract: The influence of near ultraviolet radiation on the electrical property of OSR second surface mirror was studied experimentally and SEM and XPS were used to analyze the surface topography and its composition. The degradation mechanism of OSR electrical property was analyzed. From test and analysis, it is found that the surface resistivity of OSR decreases with near UV irradiance exponentially, and the resolution of adsorption oxygen in oxygen vacancy, rupture of In-O bond and increase of oxygen vacancy are the major causes for the improvement of electrical properties of OSR irradiated by near ultraviolet.