The highly efficient biological aeration filter-cell(BAF) process has been used in the treatment of sewage, and the results indicate that the specifications of COD_Cr,BOD₅,SS in the treated water are much better than the requirements in quality standard of domestic water (CJ 25.1-1989), the average concentrations of the treated water are: COD_Cr≤20 mg/L, BOD₅≤3.5 mg/L, SS≤1.0 mg/L. This BAF process is of such excellent properties as less investment, high efficiency and simple operation, which deserves popularization and application in the field of sewage reused treatment industry.