NOVELTY - Denitrification and desulfurization comprises forming stable and mature granule sludge, using active sludge of sewage treatment plant sedimentation tank, adding to expand grain sludge bed reactor, introducing wastewater I, regulating at 27-29 degrees C, adding sodium bicarbonate, controlling hydraulic retention time for 24 hours, running for 25 days, forming stable and mature granule sludge and expanding grain sludge bed reactor in the wastewater I; and forming expand and particle sludge bed reactor of grain mud stable and mature into wastewater II, and completing denitrification.    USE - Method of denitrification and desulfurization (claimed).    ADVANTAGE - The method is stable, and removes nitrate and acetate at more than 95%.    DETAILED DESCRIPTION - Denitrification and desulfurization comprises forming stable and mature granule sludge, using active sludge of sewage treatment plant sedimentation tank, adding to expand grain sludge bed reactor, introducing wastewater I, regulating at 27-29 degrees C, adding sodium bicarbonate, controlling hydraulic retention time for 24 hours, running for 25 days, forming stable and mature granule sludge and expanding grain sludge bed reactor in the wastewater I; and forming expand and particle sludge bed reactor of grain mud stable and mature into wastewater II, with temperature regulating expand grain sludge bed reactor at 27-29 degrees C for 6.4-11.2 hours, operating for 73 days, and completing denitrification. The wastewater I comprises 1000 mg/L sulfate (SO42), 500 mg/L nitrate (NO3), 220.6 mg/L dipotassium phosphate trihydrate (K2HPO4.3H2O), 573.2 mg/L ammonium chloride (NH4Cl), 25 mg/L calcium (Ca2+), 10 mg/L magnesium (Mg2+), 2000 mg/L chemical oxygen demand (COD), and 0.5-2 mL/L microelement liquid; and trace element liquid comprising 500 mg/L zinc chloride (ZnCl2), 500 mg/L ammonium molybdate tetrahydrate ((NH4)6Mo7O24.4H2O), 500 mg/L nickel chloride (NiCl), 500 mg/L boric acid, 500 mg/L aluminum chloride, 500 mg/L cobalt chloride, 500 mg/L copper sulfate, 1000 mg/L sodium selenite (NaSeO3), 1500 mg/L iron chloride, 5000 mg/L magnesium chloride and 5 mL/L 37% hydrochloric acid aqueous solution. The wastewater II comprises 200-800 mg/L sulfur (S2), 87.5-530 mg/L NO3, 77.5-300 mg/L carbon, 6.2-24.8 mg/L K2HPO4.3H2O, 28-112 mg/L NH4Cl, 750-3000 mg/L sodium bicarbonate, and 0.5-2 mL/L trace element liquid.