NOVELTY - An urban sewage nitrogen and phosphorus removal treatment method comprises sending pre-treated urban sewage and digested sludge refluxed by an anaerobic sludge digestion unit into an anaerobic reactor; sending outlet water of the anaerobic reactor to an anoxic reactor together with the mixed solution refluxed by the anaerobic reactor and refluxed sludge; sending the mixed solution of the outlet water of the aerobic reactor to a secondary sedimentation basin to separate sludge and water; and discharging the remaining active sludge to the anaerobic sludge digestion unit.    USE - An urban sewage nitrogen and phosphorus removal treatment method.    ADVANTAGE - The method has low energy consumption.    DETAILED DESCRIPTION - An urban sewage nitrogen and phosphorus removal treatment method , where nitrogen and phosphorus are removed through comprehensive utilization of sludge anaerobic digestion and sewage anaerobic and aerobic biologic nitrogen and phosphorus removal treatment technology to largely increase the methane yield, and through the recycling of the energy of the methane, energy consumption (electric energy and thermal energy) of sewage and sludge treatment can be provided, comprises:    (A) sending pre-treated urban sewage and mixed solution b from an anoxic reactor into an anaerobic reactor, while sending partial or all digested sludge refluxed by an anaerobic sludge digestion to anaerobic reactor; aerating or stirring the sewage and the sludge to form a mixed solution a;    (B) flowing the mixed solution a and refluxed sludge from a secondary sedimentation basin into the anaerobic reactor, while sending part or all digested sludge refluxed by an anaerobic sludge digestion unit to an anoxic reactor; refluxing the mixed solution d to the anoxic reactor from an aerobic reactor; and aerating or stirring the sewage and the sludge to form a mixed solution c;    (C) flowing the mixed solution c into the aerobic reactor from the anoxic reactor, while sending part or all digested sludge refluxed by an anaerobic sludge digestion unit to the aerobic reactor; refluxing one part (mixed solution d) of the mixed solution flowing out from the aerobic reactor to the anoxic reactor while sending the other part (mixed solution e) to secondary sedimentation basin;    (D) after the mixed solution e enters the secondary sedimentation basin, discharging the clarified sewage out of the system as outlet water; discharging the sludge from the bottom of the secondary sedimentation basin, where most of the sludge enters the anoxic reactor as the refluxed sludge; and the remaining sludge is discharged to a sludge concentrating unit;    (E) in the sludge concentrating unit, discharging the concentrated sludge to the anaerobic sludge digestion unit to be digested; refluxing the removed water (such as supernatant) in the sludge to sewage pre-treatment; and    (F) digesting the sludge in anaerobic sludge digestion unit under the anaerobic condition to generate marsh gas with methane as main and digested sludge; in the discharged sludge of the sludge digestion unit, one part of the digested sludge is all refluxed to the anaerobic reactor or the anoxic reactor or the aerobic reactor, or is respectively refluxed to the anaerobic reactor or the anoxic reactor or the aerobic reactor according to a proportion; the other part of the digested sludge is dehydrated and disposed according to national requirement.