TiO2 powder was prepared by sol-gel method using butyl titanate as precursor in alcohol solution. The prepared powder was characterized by UV and XRD. The effects of calcination temperature, crystal ratio, the initial pH of preparation solution on structure and photocatalytic activity of TiO2 powder were analyzed. Results showed that anatase type TiO2 transferred into crystalline rutile TiO2 at approximately 700 ℃. The product crystal form was anatase when the pH of initial gel was 4, cinder temperature 600 ℃. The ratio of anatase type TiO2 to crystalline rutile TiO2 would affect the photocatalytic activities. When the volume ratio of absolute ethyl alcohol and butyl titanate was 10∶1, the product grain size was 617 nm; the optimal catalytic effect and degradation rate was got with the preparation solution pH value being 4, calcination temperature 600 ℃ and time of 40~60 min. With the photocatalysis system pH being 9, soaked in methylene solution of 10 mg/L for 2 h, TiO2 being 0.25 g/L, the degradation rate reached 95.3%.