Styrene had been oxidized by using phosphor-tungstic acid as the catalyst, urea peroxide as an oxidant, and methanol as the solvent. The experimental results showed that phosphor-tungstic acid had higher catalytic activity; the conversion of styrene and the yield of epoxy benzethane and the selectivity of epoxy benzethane arrived at 93.2, 81.2, and 87.2%, respectively. The effects of the reaction condition on the epoxidation reaction were checked. When the ratio of urea peroxide, styrene, and phosphor-tungstic acid was 511.8:255.9:1, the yield of epoxy benzethane reached maximum value. The effect of stannic tetrachloride was examined. The experimental results indicated that the selectivity of epoxy benzethane was increased by adding stannic tetrachloride.