Surface modification method of nano-titanium dioxide

The invention relates to a modification method of nano-titanium dioxide. The modification method comprises the steps of (1) adding nano-titanium dioxide powder into an ethanol solution, and performing ultrasonic vibration to uniformly mix the nano-titanium dioxide powder in the ethanol solution to obtain the ethanol solution of the nano-titanium dioxide; (2) adding a silane coupling agent KH-570 into a mixed solution of ethanol and deionized water, and performing ultrasonic vibration to hydrolyze the silane coupling agent KH-570 in the mixed solution; (3) adding the mixed solution after hydrolysis, which is obtained in the step (2), into the ethanol solution obtained in the step (1), performing ultrasonic vibration, and then stirring for reacting at the temperature of 70-90 DEG C; performing suction filtration, washing, drying and grinding to obtain the surface modified nano-titanium dioxide. The dispersity of the nano-titanium dioxide modified by the silane coupling agent KH-570 is improved, so that the weatherability, the ultraviolet resistance and the like are improved. The modification method provided by the invention has the advantages of low price of raw materials, simple process and low cost, and is favorable for industrial production.