NOVELTY - Intermittent denitrification method for ground water, comprises: (a) carrying out enrichment culture on denitrification bacteria, inoculating in the active sludge of the city life sewage treatment plant; (b) preparing polyvinyl alcohol solution, dissolving solid polyvinyl alcohol solution to distilled water; (c) preparing tabulate fixed cell, centrifuging the denitrification bacterial suspension; (d) building bioreactor for fixed cell membrane, covering micropore filter film; (e) carrying out denitrification for ground water, adding the ground water and the ethanol aqueous solution.    USE - The intermittent denitrification method is useful for ground water.    ADVANTAGE - The method can prevent the ground water from being polluted by the denitrification bacterial and also can effectively prevent the pollution of the denitrification residual organic carbon source to the ground water, so the safety of the drinking water is ensured.    DETAILED DESCRIPTION - Intermittent denitrification method for ground water, comprises: (a) inoculating the active sludge of the city life sewage treatment plant to the denitrification bacterial culture liquid, stirring with a stirring reactor to suspend the sludge, and then carrying out enrichment culture on denitrification bacterial, stirring to react for 20-22 hours every day, standing to precipitate for 2-4 hours, removing the supernatant by siphonage, and then adding fresh denitrification bacterial culture liquid to carry out the next turn of operation, operating continuously for more than 60 days to obtain the denitrification bacterial suspension; (b) dissolving the solid polyvinyl alcohol solution to the distilled water of 6.5 times by weight of polyvinyl alcohol while heating, thus the polyvinyl alcohol aqueous solution with concentration of 13-15% (w/v) is obtained, and then adding the glycerin of 2-6% (v/v) by volume of polyvinyl alcohol aqueous solution to be the anti-freezing agent and uniformly stirring for use; (c) centrifuging the denitrification bacterial suspension from step (a) at 3000 revolution/minute to concentrate, removing the supernatant, washing and centrifuging with physiological saline for 2 times and then adding the concentrated strain to the polyvinyl alcohol solution from step (b), where the adding quantity of the wet strain is 10-50 g/L and then uniformly stirring, flatly paving in a plate frame-like mould, freezing in a refrigerator from -19 to -21 degrees C for 12-16 hours and then thawing for 2-4 hours at room temperature, repeating the processes of freezing-thawing for 4-6 times and fully washing the surface of the film by distilled water to obtain the tabulate fixed cell; (d) covering micropore filter film with pore diameter of 0.22 microns or 0.45 microns on the surface of one lateral of the tabulate fixed cell from step (c) and then fixing the tabulate fixed cell and the micropore filter film together in the shell of reactor by flange and bolt, to obtain bioreactor for fixed cell membrane; and (e) adding the ground water and the ethanol aqueous solution respectively in different chambers of the bioreactor for fixed cell membrane, adding the ground water polluted by nitrate, adding the ethanol aqueous solution to the two lateral chambers, opening a stirrer to carry out the denitrification, controlling the ratio of the total quantity (by chemical oxygen demand analysis by the conventional dichromate method) of ethanol in two lateral chambers to the total quantity of the nitrate nitrogen in middle chamber within 4-6, and stopping the reaction when the concentration of the nitrate nitrogen in the ground water meets the limitation value of nitrate namely nitrate ion nitrogen is less than or equal to 10 mg/L, where the ethanol for the denitrification is added for one time at the beginning of reaction.