High-concentrated sulfur waste water from a certain factory in Jiangsu was treated by the process of jarosites deposition. In this paper, a method for treating high-concentrated sulfur waste water in the industry is discussed. The experiment utilized the deposition process to remove parts of SO 2- _4, caused the continuous transform of low-valence S into SO 2- _4 and oxidized low-valence S by H_2O_2. The second deposition could remove more S, thus sharply decreasing the COD of the waste water. According to the experimental results, the optimal operational parameters are confirmed,the pH value is between 2.50 and 3.20,and the optimal FeCl_3 addition amount is 50 g/L. The whole waste water flow needs two deposition processes,which make the disposal rate COD of the waste water up to 85.29%. And the disposal rate COD of the waste water can eventually reach 96% by H_2O_2 oxidation. The results obtained provide fundamental data for practical operation before biochemical treatment.