NOVELTY - Biological control method of biomass excessive accumulation in waste gas biofilter includes selecting nematode and ciliate that grow normally; introducing target waste gas i.e. toluene into inorganic salt liquid culture medium continuously, where toluene has a concentration of 80-150 mg/m3; and acclimatizing the nematode and ciliate with strong tolerance to target waste gas and large predation biomass, where removal rate of toluene degrading bacteria reaches 99-100%, and when the concentration of toluene reaches 600 mg/m3, the growth of the nematode is restrained.    USE - Biological control method of biomass excessive accumulation in waste gas biofilter (claimed).    ADVANTAGE - The method can effectively control biomass excessive accumulation in waste gas biofilter; realize zero growth of biofilm; and maintain long-term stable running of biofilter.    DETAILED DESCRIPTION - Biological control method of biomass excessive accumulation in waste gas biofilter comprises:    (A) selecting nematode and ciliate growing normally from an active sludge as microfauna of high nutrition level;    (B) screening toluene degrading bacteria from biofilter;    (C) introducing target waste gas i.e. toluene into a conical flask with inorganic salt liquid culture medium continuously; and acclimatizing the nematode and ciliate with strong tolerance to target waste gas and large predation biomass, where toluene has a concentration of 80-150 mg/m3, and removal rate of toluene degrading bacteria reaches 99-100%, and when the concentration of toluene reaches 600 mg/m3, the growth of nematode is restrained, the growth of ciliate is normal, and the growth speed of toluene degrading bacteria is reduced, and when the concentration of toluene reaches 900 mg/m3, the growth of ciliate is also restrained;    (D) culturing the acclimatized ciliate and nematode; inoculating the target waste gas degrading bacteria on liquid beef extract peptone culture medium; at 28 degrees C, oscillating and culturing for 48 hours at 180 times/minute by a table concentrator; obtaining bacterium liquid; adding bacterium liquid onto common culture medium of nematode and ciliate; adding acclimatized and sterilized nematode and ciliate; putting into constant temperature and constant humidity culture medium; at 50-60% humidity and 25 degrees C, culturing for 7 days; and obtaining the needed inoculated nematode and ciliate; and    (E) inoculating the cultured nematode and ciliate into biofilter.