Abstract: TiO₂ was prepared by sol-gel method, and used for solar photocatalytic degradation of trichlorfon wastewater. Molybdenum blue colorimetric method was used to determine trichlorfon mineralized to inorganic phosphorus rate. COD value in the degradation process was determined by KMnO₄ method in acid solution, and UV trace organic phosphorus changes during the reaction of the intermediate product. The obtained sample was characterized by IR and X-ray Diffraction (XRD) and UV-vis. The results showed that the optimum roasting temperature of catalyst is 500 ℃, 2 h, the dosage of catalyst is 4 g/L and the initial concentration of phosphorus is 4 mg/L. Under the condition of reaction 90 min, the photocatalytic activity of pure TiO₂ was 91.8% and COD conversion is 76.6% under sunlight. Characterization results showed that TiO₂ (500 ℃, 2 h) prepared by sol-gel method was anatase, and had the strongest uv-light absorption capacity, resulted the best photocatalytic activity.