The invention discloses a fast biofilm formation method for an organic filler during treatment of sewage with a low C/N ratio, and belongs to the field of biofilm process for sewage treatment. The invention improves the effect of biofilm culturing by changing the micro-interface acting force of the filler and accelerating the attachment and colonization of microorganisms on the filler through increase of bacterial quorum-sensing molecules. As compared with a conventional biofilm culturing method, in the invention the biofilm culturing is rapid and operated conveniently, has strong practicality, and is a fast biofilm formation method for an organic filler, which is adapted for treatment of sewage with a low C/N ratio under an aerobic, anoxic or anaerobic condition.