The invention discloses a sludge treatment method capable of reducing discharge of nitrogen oxide in a pulverized coal boiler at the same time. The sludge treatment method comprises following steps: dividing the pulverized coal boiler into a primary burning area, a re-burning area and a burning-out area from the bottom to the top along the height direction of a hearth and conveying pulverized coal into the primary combustion area for burning; adopting a coal pulverizer to grind sludge into powder and utilizing high-temperature flue gas in of the boiler to dry sludge powder, and conveying dried sludge powder into a sludge powder bin and conveying exhaust gas with dried sludge into a condenser for condensation and water removal; utilizing exhaust gas after condensation and water removal and high-temperature flue gas to convey dried sludge powder from a burner of the re-burning area to the hearth and burning in the reducing atmosphere; and finally conveying air from the burning-out area in order to ensure that bunkers are completely burned out. The sludge treatment method capable of reducing discharge of nitrogen oxide in the pulverized coal boiler at the same time has following beneficial effects: by utilizing present characteristics of the pulverized coal boiler and highly-volatile sludge, a reduction reaction of NO is made by hydrocarbon groups which are formed by burning of sludge, thereby achieving emission reduction of NO and highly-efficient low-pollution processing of sludge; and the purpose of using waste to treat waste is fulfilled.