The surface optical performances of K9 glass plate through different chemical cleaning procedures were synthetically characterized by p-polarized reflectance method, atomic force microscopy and laser damage test. The results show that the extinction coefficient of glass surface with acid erosion decreases clearly, and its fineness and laser-induced damage threshold increase accordingly. Further the glass surface optical performances can be improved through alkaline cleaning. In addition, with the development of cleaning program of glass plate, the changing trend of glass surface optical parameters measured by p-polarized reflectance, accord with that of observed surface roughness and damage threshold.