Abstract: A 200 m³/d biochemical-ultrafiltration wastewater treatment process was established at a water injection station in Shengli oilfield, which was used for low permeability reservoir reinjection. The biochemical process adopted mobile bed biofilm (MBBR) process with tubular hollow fiber membrane was used for ultrafiltration. The water quality analysis, process start-up, initial debugging and water quality tracking detection of different nodal water were studied in depth. The system was put into operation in June 2018 with a normal operation till now. Through the treatment process, the pressure difference of ultrafiltration across the membrane increased from 0.018 MPa to 0.028 MPa, the oil concentration of sewage decreased from 12-659 mg/L to 0.0-0.3 mg/L, and the concentration of suspended matter decreased from 15-255 mg/L to 0.1-0.3 mg/L. Additionally, the number of SRB decreased from 25-60/mL to 0, the median particle size decreased to 0.86 -1.00 μm, and the COD value decreased from 216-505 mg/L to 73-123 mg/L, showing better effects than a class of water of SY/T 5329-2012.