Workmen for the wastewater treatment advocated wastewater reusing in the conference which the technically development and strategic research of China are main topic.Biofilter is useful as tertiary biofilm reacter.However, it often accrues clogging during cold period and needs frequent backwashing. Backblowing and partial backwashing can slow it. The average flux rised from 2.65 m3/m2.h to 2.84 m3/m2.h. The removal of NH3-N of cocurrent-flow and counter-flow biofilter can be improved. The parameter of partial backwashing depended on the rate of expanding.of counter-flow biofilter.The effect of different backblowing parameters on flux of cocurrent-flow biofilter would be described in this paper. From the parameters studied the bioifiltration time is the most important factor affecting the flux. The results show that the best flux is obtained when backblowing was made for 60s every 12h during 72h where the air pressure was 63 m3/m2.h and water pressure was 25.2 m3/m2.h.