Abstract: In order to improve its waterproof effect, WD-10, with the main component of dodecyltrimethoxysilane, is modified by nano TiO2 with KH550 (3-aminopropyltriethoxysilane) as the coupling agent and OP-10(polyethylene glycol octyl phenyl ether) as the emulsifier. The characteristics, including water repellence, gas permeability, salt resistance, light resistance and climate resistance, were characterized. The results have been shown that the modified material possesses excellent water repellence and gas permeability with the contact angle of about 140? and the permeable percentage of 8% higher than that of WD-10. After two ageing cycles with saline solution, there was a 61.48 percent decrease in the weight loss rate comparing with WD-10. It was shown that the contact angle of WD-10 reduced to zero after 816 hours of UV aging, while the contact angle of the modified material was more than 90? From the 240h of laboratory climate aging of fine sandstone rock of Chongqing Dazu carvings, the World Cultural Heritage, the results showed that weight loss of modified material was only 1.07% and the contact angle changing rate was 10.38%, both were less than 1.95% and 24.34% of WD-10. Therefore our self-developed waterproof material of stone relics, WD-10 modified by nano TiO2, improves better than WD-10 on the gas permeability, salt tolerance, light resistance and climate resistance. Moreover, excellent water repellence can keep for a long time.