Abstract: To improve wood color stability, UV absorber and heat treatment were applied to modify the coatings and substrate, respectively. Color stability of heat treated and untreated wood of three species was studied using xenon-arc lamp aging method. The inhibitory effects of modified PU coating on photo-induced aging were also analyzed. Results showed that, the color stability was improved obviously after heat treatment. After exposure to xenon-arc light for 100 hours, color differences of Dipterocarpus turbinatus, Pinus sylvestris var. mongolica and Cunninghamia lanceolata was decreased 38%, 29% and 59%, respectively. Compared to control coatings, modified PU coatings could increase color stability by 14% to 61%. Keruing wood displayed the best color stability, whereas pine wood performed the worst among the three species. Wood species and heat treatment condition should be considered in the development of paint for outdoor cases.