NOVELTY - Method for treating sewage, involves (a) building an integrated compound film bioreactor, (b) adding the hollow suspension filler fixed with cold-resisting bacteria on surface of reactor, (c) leading sewage to be treated to the integrated compound film bioreactor through a water inlet, controlling water chemical oxygen demand (COD) concentration, and performing micropore aeration for the reaction pool, (d) performing sludge-water separation, and performing micropore aeration, and (e) draining the treated water through water outlet.    USE - The method is useful for treating sewage.    ADVANTAGE - The method builds reactor which is capable of running even at 5-15 degrees C. The treated water COD concentration is less than 50 mg/l.    DETAILED DESCRIPTION - Method for treating sewage, involves (a) building an integrated compound film bioreactor, where the integrated compound film bioreactor comprises water inlet, filter, filtering film, water outlet, reaction pool, micropore aeration device which is mounted under the reaction pool, and filtering film which is an ultrafiltration membrane or microfiltration membrane, (b) adding the hollow suspension filler fixed with cold-resisting bacteria on surface of reactor under large surface area and stable inner environment of hollow suspension filler to increase surface fixing action of the microorganism, where the filler space proportion is 30-50%, and domestication and film hanging period is 15-30 days, and storing the cold resisting bacteria tolerant to actinomycetes and mycete in a refrigerator before fixing on the suspension filler, (c) leading sewage to be treated to the integrated compound film bioreactor through a water inlet, controlling water chemical oxygen demand (COD) concentration between 50-400 mg/l, where the sludge concentration is 2-4 g/l and water is stagnated in the reaction pool for 11-13 hours, and performing micropore aeration for the reaction pool, where the air water ratio is 10:1-30:1 and under low temperature running condition the cold resisting bacteria in the active sludge in reactor is slowly adhered, fixed and enriched on the suspension filler to maintain the stable treatment effect of the compound film bioreactor, (d) performing sludge-water separation for the sewage performed by biochemical treatment through ultrafiltration membrane or microfiltration membrane which has high efficiency blocking action, and performing micropore aeration for the filtering film, where the microorganism is blocked in the reaction pool, and (e) draining the treated water through water outlet.