Studies have shown that nanometer Titanium dioxide is an excellent photocatalyst material, which owns environmental protection function of decomposing car exhaust, and it begins to be used in road works in recent years. In this paper, firstly a representative concentration ratio of each component in exhaust gas is reached according to statistical result from a large number of vehicle exhaust samples, and simulated gas used in laboratory test is prepared according to the ratio. Then substantial gas- decomposition tests are performed utilizing the self-designed sealed container and UV aging box. Applying ion chromatography to analyze the decomposition products, it is proved that nano-titanium dioxide can decompose NOx, HC, CO and other harmful gases into nitrate and carbonate. Subsequently, an excellent concrete protection materials- anticorrosive of silane solvent is selected as dispersion solvent, and a certain amount of titanium dioxide is dispersed evenly in the solvent to make the coating material with photocatalytic performance, the brushing method and decomposition effect of the coating material are discussed. In the end, a brushing method with better decomposition effect is applied on cement collision wall on middle ring in Pudong district, while nano-titanium is also contained in the surface layer of pavement; Field measurement results show that the decomposition of car exhaust effect is obvious.