NOVELTY - Anaerobic-anoxic-oxic (A-A-O) treating sewage by removing total nitrogen without adding carbon source comprises removing municipal sewage intercepting pipeline network large impurities by coarse grid, setting with square cast iron gate door on coarse grid front back for inspecting, entering into water storage tank and fine grid through pump, and removing less impurities; and distributing by entering into sludge denitrifying tank, biochemical tank anoxic zone and rotary flow tank, and entering into sand water separator to separate sand, and entering into biochemical tank anaerobic area.    USE - Method for A-A-O treating sewage by removing total nitrogen without adding carbon source (claimed).    ADVANTAGE - The method has biochemical removing rate reaching to 63%, increases nitrogen removal efficiency, and eliminates adverse influence after anaerobic tank phosphorus release.    DETAILED DESCRIPTION - Anaerobic-anoxic-oxic (A-A-O) treating sewage by removing total nitrogen without adding carbon source comprises:    (A) removing municipal sewage intercepting pipeline network large impurities by coarse grid, setting with square cast iron gate door on coarse grid front back for inspecting, entering into water storage tank, entering into fine grid through pump, and removing less impurities;    (B) distributing by entering 10% into sludge denitrifying tank for 1 hour, entering 15% into biochemical tank anoxic zone and entering 75% into rotary flow tank, and entering into sand water separator to separate sand, and entering into biochemical tank anaerobic area;    (C) entering effluent from anaerobic area water outlet into A-A-O section and aerobic zone I for hydraulic retention time of 4.3 hours to sludge concentration of 2800-3500 mg/L, reaching for 25-30 days, and nitrifying to ensure ammonia-nitrogen standard;    (D) setting with main A-O section, environmental nitrifying and denitrifying, strengthening to remove nitrogen, directly entering into A-O section, controlling dissolve oxygen at 0.3-0.5 mg/L at hydraulic retention time of 3.6 hours and aerobic zone II residence time of 4.3 hours, and controlling dissolve oxygen to 2-4 mg/L;    (E) entering into sediment tank for solid-liquid separation, discharging, purifying into filtering tank, reflux pumping into sludge denitrifying tank and anoxic tank, and reflux pumping by pressurizing sending into sludge concentration tank;    (F) flowing to filtering tank, removing water suspension object and nitrogen organic matter, entering sterilizing channel through filter for UV sterilizing processing, and discharging water into guide flow passage;    (G) reflux pumping from biochemical tank anaerobic area, discharging, sludge concentrating, sending medicament polyacrylamide, mixing, dewatering, transporting by belt conveyer into vehicle, and incinerating; and    (H) reducing phosphorus amount in water to less than 0.5 mg/l, flocculating and sedimenting at biochemical tank water outlet added with less phosphorus removal medicament aluminum sulfate, discharging through filtering, sterilizing, and ensuring water standards.