Based on the mechanism of biological phosphorus and nitrogen removal, the collision between on nutrient and resident time is given. In order to solve this problem, a new process for wastewater biological treatment- three-stage SBR process has been developed. Three- stage SBR process treat domestic sewage is applied, which controls various kinds of bacteria optimum growth with the different function that responsibility for removal organics, nitrogen and phosphorus existed in the different reactors and combine with the denitr/fying phosphorus removing process . The experiment results show that ,the three-stage SBR process not only improved the treatment efficiency that COD ,TN,and TPaverage removal efficiency is 87% ,80% and 86% , but also saved the energy cost. removal. The process can make better effect on simultaneous nutrients removal, simple operation and low cost will make a good application prospect for it.