By the study of the influence of COD concentration on denitrifying phosphor removal of A/ASBR (anaerobic/ aerobic sequence bioreactor), it was shown that the favorable treatment effect had been gained with the COD concentration between 220 and 300mg/l; the higher or lower concentration of COD was unfavorable to the work of the system. In our test, it has been confirmed that the rudimental carbon resource organism and cell depositor PHB deposited in anaerobic stage has a significant influence on the process of denitrifying phosphorous removal. The better correlation has been observed also between the consumption of PHB and denitrifying phosphorous removal when the use of cell depositors PHB as carbon resource is concerned. It indicates that the deoxidization of 2 mg nitrate may accelerate the absorption of 1 mg phosphorous.