The treatment effects of the fixing liquid developer mixed wastewater in the photographic industry were researched by using the pretreatment method and the biological treatment method of flocculation precipitation. During the pretreatment experiment of coagulation method, the mixture solution after silver extraction were pretreated by adding calcium ions, polyaluminum chloride and anionic polyacrylamide. When the dosage of calcium chloride is 5 g/L, the pH value is 9 ( calcium oxide dosage is 3 g/L ), 5% polyaluminum chloride dosage of aluminum chloride is 40 mL/L, 1‰ of anion polyacrylamide is 50 mL/L, the total removal rate of water sample CODCr could reach about 30%, the salt removal rate is about 37%. When the residence time in the anaerobic pool is 24 h, the first-grade aerobic pool and the secondary aerobic pool are all 6 h, the total removal rate of water sample CODCr could reach about 70.46%. The concentration of water samples is greatly reduced and the harm is greatly reduced.