The invention discloses a granular sludge-based integrated anaerobic ammonium oxidation denitrification reactor and a method, relates to a granular sludge-based shortcut nitrification-anaerobic ammonium oxidation integrated denitrification reactor and a starting method, belongs to the technical field of biological sewage treatment and aims to solve the technical problems that nitrite nitrogen in a mixed solution reacts with ammonia nitrogen to generate nitrogen during a precipitation stage, the nitrogen is combined with floc sludge, and upward floating of the floc sludge can be caused, so that the effluent quality is deteriorated. The granular sludge-based integrated anaerobic ammonium oxidation denitrification reactor comprises an aeration pump, a flow meter, an aeration disk, a blow-down pipe, a water inlet pipe, sampling openings, a water bath sleeve, a reaction pipe, an online monitor, a three-phase separator, an annular water outlet tank, a sawtooth-shaped end surface, a water outlet pipe, a gas outlet pipe, a water sealed exhaust pipe, a water inlet barrel and a water inlet pump. The method comprises the following steps: 1, system booting; 2, program running; 3, stable running of the reactor. By adopting the granular sludge-based integrated anaerobic ammonium oxidation denitrification reactor disclosed by the invention, a removal rate of total nitrogen is higher than 85 percent.