The paper aims to introduce our research on optimizing the parameters of biodegradating nitrobenzene by means of improving its orthogonal layout. As is known,biodegradation is one of the best ways to treat nitrobenzene contamination. However,since it is complicated and inconvenient to be treated,it is necessary to take the trouble to optimize the parameters of degradation,that is to say,it is necessary to isolate a number of strains of bacteria that can degrade nitrobenzene from the contaminated sludge of c...