In order to reduce wastewater discharge and environmental pollution,and save water resources, the combined process of hydrolysis acidization, biological contact oxidation, coagulation and sedimentation and filtration was used to treat PVC centrifuge liquid wastewater in the chlor-alkali industry. The engineering design and treatment scale is 1 000 m3/d, the design water quality COD is 200 to 350 mg/L, the BOD5 is 60 to 150 mg/L, the SS is 100 to 300 mg/L, and the temperature is 60 to 70 ℃. After this process, the effluent water quality meets the cooling water quality standards stipulated in the "Industrial Water Quality for Urban Sewage Recycling"(GB/T19923-2005) and is reused for production. That is, COD ≤ 60 mg/L, BOD5 ≤ 10 mg/L, turbidity ≤ 5 NTU. The engineering example proves that the technology has the characteristics of simple operation, low investment and operation cost and no secondary pollution, and has achieved good economic and environmental benefits.