The invention discloses a method for synthesizing a rutile TiO2 nanowire array by soft chemistry and hydrothermal technology. The method has the characteristics of low preparation temperature, simple application technology, large specific surface area and high photo catalytic activity of the obtained photocatalyst, and the rutile serving as a main body. Hydrochloric acid, toluene, titanium tetrachloride, and tetrabutyl titanate are weighed according to a certain ratio, the toluene is used as a solvent, and solution of titanium tetrachloride and solution of tetrabutyl titanate are prepared respectively. The method for preparing the TiO2 nanowire array comprises the following steps of: (1) cleaning a glass slide which is cleaned by solution of ethanol into an ultrasonic cleaner for several minutes, and cleaning the glass slide by using deionized water; (2) weighing a certain amount of tetrabutyl titanate and titanium tetrachloride according to the stoichiometric ratio respectively, and dissolving the tetrabutyl titanate and titanium tetrachloride in a certain amount of solution of toluene respectively; (3) putting the cleaned glass slide into a sealed reaction kettle which is made of stainless steel and has a white polytetrafluoroethylene lining, and adding a certain amount of hydrochloric acid; (4) guiding the flow by using a glass rod, slowly adding a certain amount of solution of toluene, tetrabutyl titanate, and titanium tetrachloride; (5) putting the reaction kettle into a drying oven for heat treatment, wherein the reaction temperature is between 130 and 180 DEG C, and the reaction time is 6 to 22 hours; and (6) naturally cooling the reaction kettle at room temperature, and taking the glass slide out, and drying so as to obtain the TiO2 nanowire array.