NOVELTY - An improved sequencing batch fermentation coupling denitrification reactor comprises first water tank with inlet valve and peristaltic pump connected to the sludge fermentation coupled denitrification reactor installed with a stirrer and an external temperature control box connected to the heating rod and temperature sensor, gas collection device, and on both sides are the oxidation-reduction potential online analyzer and pH-line analyzer; sludge storage tank with mud pump connected to the fermentation reactor; and second water tank connected to the fermentation reactor through the valve.    USE - Improved sequencing batch fermentation coupling denitrification reactor used for intensified denitrification of carbon/nitrogen ratio of urban sewage (claimed).    ADVANTAGE - The device is suitable for low carbon/nitrogen ratio of urban sewage, can save carbon, improves nitrogen removal efficiency, creatively uses micro-oxygen limited aeration, and has an effective control of releasing ammonia and carbon enhanced denitrification sludge which improves the water quality.    DETAILED DESCRIPTION - An improved sequencing batch fermentation coupling denitrification reactor comprises first water tank (1) with inlet valve (2) and peristaltic pump (4) connected to the sludge fermentation coupled denitrification reactor (5) installed with a stirrer (10) and an external temperature control box (13) connected to the heating rod (11) and temperature sensor (12), gas collection device (14), and on both sides are the oxidation-reduction potential online analyzer (15) and pH-line analyzer (16); sludge storage tank (6) with mud pump (7) connected to the fermentation reactor; and second water tank (9) connected to the fermentation reactor through the valve (8). An INDEPENDENT CLAIM is included for denitrification of sewage by pretreating wastewater with aerobic nitrification liquid, introducing into the fermentation coupling denitrification reactor at alternating anaerobic-anoxic environment, fermenting primary sludge substrate by enriching with culture fermented bacteria and denitrifying bacteria for a week, anaerobically mixing, adding water and oxygen, precipitating, draining; pumping mud from the sludge storage tank into the fermentation tank, setting volume of mud and of the reactor which is 1/20, and agitating for 9-20 hours; continuously agitating, setting water into the reactor at volume ratio of 1/2, opening first water tank, and pumping into the fermentation reactor; opening inlet valve, pumping outside air into the fermentation reactor to remove ammonia, measuring dissolved oxygen (DO) concentration, and closing the inlet valve and peristaltic pump when DO is greater than 0.2 mg/L or intake time is greater than 20 minutes; anoxic mixing, online monitoring of pH and ORP, stopping oxygen mixing time control pH or ORP inflection point when dpH/dt is less than or equal to 0 and t is greater than or equal to 30 minutes or dORP/dt is less than or equal to - 50 and t is greater than or equal to 30 minutes, and turning off agitator stopping the stirring; precipitating for 1-2 hours, separating mud, draining at volume ratio of 1/2 by a control switch, discharging supernatant liquid at volume of 1/20 through the drainage valve, setting the drainage into idle period for 1-2 hours until mud phase is completed at volume ratio of 1/20.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of improved sequencing batch fermentation apparatus.    First water tank (1)    Inlet valve (2)    Peristaltic pump (4)    Sludge fermentation coupled denitrification reactor (5)    Sludge storage tank (6)    Mud pump (7)    Valve (8)    Second water tank (9)    Stirrer (10)    Heating rod (11)    Temperature sensor (12)    External temperature control box (13)    Gas collection device (14)    Oxidation-reduction potential online analyzer (15)    PH-line analyzer (16)