Abstract: In order to make the phosphorus removal ability of the activated sludge in the original process further improved,the strain P2 was added to the original sludge after expanding culture,then through CASS reactor according to the approximation optimal phosphorus removal conditions to the strain P2 was domestication,and to detect the related sewage discharge index in the domestication process. When domesticated conducted to 15 d,the various indicators of effluent as phosphorus removal rate were basically stable,ending the first phase of domestication.Then inspect the sludge impact resistance,study on in different temperature,time,p H value and reaction parameters to the phosphorus removal ability,the results showed that the suitable p H was 7.0,a suitable temperature was 35 ℃,the change frequency was 20 min between the anaerobic and aerobic,and the anaerobic time was 1.5 hours.which the phosphorus removal rate reached 93.6%. In the optimum domesticated conditions,some phosphorus accumulating organisms,was not dominant in previous sludge,such as the strain p2,were due to be changed to the main organisms after being domesticated,the activated sludge microbial community structure changed greatly.