NOVELTY - In-situ restoration of polluted water body comprises using membrane-suspended floating chain aeration, where sewage enters a first reaction region discontinuously according to operational cycle, and continuous aeration is carried out with a membrane-suspended floating aeration device in first reaction region so that sewage is mixed fully with active sludge placed in first reaction region. Intermittent aeration is carried out with second membrane-suspended floating aeration device. Precipitation is then performed, and then supernatant is drained.    USE - Method of in-situ restoration of polluted water body of river or reservoir.    ADVANTAGE - The method uses floating aeration chains as aeration devices and attaches biomembranes to branch chains of floating chains via filler suspended on branch chains so as to restore and improve the quality of polluted water area. The method is economical and efficient, has stronger applicability to change of water quality and water amount, and can purify polluted water with no sludge being left even at low temperature. The quality of the treated water is improved, and restoration effect is good.    DETAILED DESCRIPTION - In-situ restoration of polluted water body comprises using membrane-suspended floating chain aeration, where sewage enters a first reaction region discontinuously according to operational cycle, and continuous aeration is carried out with a membrane-suspended floating aeration device in the first reaction region so that the sewage is mixed fully with active sludge placed in the first reaction region. Discontinuous outlet water from the first reaction region enters a second reaction region, and intermittent aeration is carried out with a second membrane-suspended floating aeration device so that the outlet water is mixed fully with the active sludge placed in the second reaction region. Precipitation is then performed, and then the supernatant is drained. The average active sludge concentration mixed liquid suspended solid in the reaction regions is 3000-5000 mg/L. An INDEPENDENT CLAIM is included for a device for restoration of polluted water body comprising a reaction tank, aeration devices, an aeration pump, air valves, a time control device, a water pump and pipelines.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of a method of restoring a polluted water body (Drawing includes non-English language text).