A biologic deodoring system for sewage and chemical odor is composed of upper and lower reactors, sprinkling cylinder, the isolating layers at both ends of said both reactor, filler in both reactor, water circulator with two sprinklers, and gas inlet and exhaust unit. Its method includes such steps as culturing active sludge, preparing film, starting system and adding circulated liquid. Its advantages are high efficiency, no blocking and small size.