The combined process of precipitation polymerization reaction, hydrolytic acidification, UASB and CASS was used to treat the wastewater from soybean protein fibre industry with a treatment capacity of 600 m3/d．The influent COD, BOD5, NH3-N and SS is 4 700 mg/L，1 200 mg/L, 21 mg/L and 300 mg/L respectively．After treatment，the effluent quality should meet the first level criteria specified in the" Integrated Wastewater Discharge Standard" (GB 8978-1996), that is COD≤91 mg/L, BOD5≤25.9 mg/L, NH3-N≤10.4 mg/L, SS≤41.8 mg/L. The engineering examples show that the process has the characteristics of low operation cost, easy management, simple operation and no secondary pollution etc..