As a new type and high efficiency and low energy consumption one in biological denitrification and phosphorus removal technology, denitrifying phosphorus removal has become a hot topic in the research field of the water treatment technology. In this technology, denitrifying phosphate removal bacteria (DPBs) plays an important role. In each process stage of an A2/O process, denitrifying phosphorus removal bacteria (DPBs) plays different function. Combining with theory of the A2/O process, the function and main influence factors of denitrifying phosphorus removal bacteria (DPBs) are studied, and the prospect about DPBs is proposed.