NOVELTY - In-situ enhancement of microbial activity comprises adding microbial inoculum into a biochemical processor for sewage treatment, adding a carrier, culture medium and glucose solution into the processor and reacting, where the microbial inoculum is prepared by inoculating Bacillus subtilis (ACCC01197), Bacillus megatherium (ACCC03116) and Pseudomonas aeruginosa (ACCC02722) into a basal culture medium, carrying out high-density fed-batch fermentation, supplementing additional carbon source, feeding glucose solution and controlling pH of 7.5-8 using aqueous ammonia.    USE - The method is useful for in-situ enhancement of microbial activity (claimed).    ADVANTAGE - The microbes reduce biochemical oxygen demand sludge conversion rate of greater than or equal to 40% during sewage treatment.    DETAILED DESCRIPTION - In-situ enhancement of microbial activity comprises: adding microbial inoculum into a biochemical processor for sewage treatment, adding a carrier, 10% culture medium and 50% glucose solution into the processor and reacting at 30 degrees C for 20-24 hours, where the microbial inoculum is prepared by inoculating Bacillus subtilis (ACCC01197), Bacillus megatherium (ACCC03116) and Pseudomonas aeruginosa (ACCC02722) into a basal culture medium, culturing for 24 hours, carrying out high-density fed-batch fermentation at 28-34 degrees C with a pH of 6-8 and dissolved oxygen content of 1-5 mg/l, supplementing additional carbon source (15 vol.% to the volume of culture medium and 50 vol.% to the volume of glucose solution) and fermenting for 80-100 hours, feeding glucose solution containing 0.1-0.2% sodium selenite into the culture medium after 24 hours of inoculation and completing the feeding within 20 hours by feeding in an increasing manner, controlling pH of the medium at greater than or equal to 6 after inoculation and maintaining pH of 7.5-8 using aqueous ammonia until the completion of fermentation; where the fermentation basal culture medium comprises 20-25 g/l glucose, 20-25 g/l peptone, 5-8 g/l sodium dihydrogen phosphate, 1-3 mg/l vitamin B1, 0.2-0.4 mg/l biotin, 0.5-0.7 mg/l niacin, 0.1-0.2 mg/l vitamin B6, 0.05-0.1 mg/l protease, 0.03-0.05 mg/l lipase, 1-3 ml/l trace element stock solution and 0.1 ml/l polyphenyl ether (PPE)-polyether efficient defoamer, adjusting pH to 6 using phosphoric acid; the trace element stock solution comprises 4 mg/ml manganese chloride tetrahydrate, 3 mg/ml cobalt chloride hexahydrate, 1 mg/ml copper chloride dihydrate, 2 mg/ml boric acid, 1.5 mg/ml sodium molybdate dihydrate, 2 mg/ml zinc acetate dihydrate and 0.5 mg/l potassium iodide; and the obtained strain composition ratio (w/w) after fermentation comprises 70-80%, preferably 75% Bacillus subtilis, 5-15%, preferably 15% Bacillus megatherium and 5-15%, preferably 10% Pseudomonas aeruginosa.