Abstract: Biodegradation is a major way of elimination of organic chemicals in the environment. Influencing factors of biodegradation of chemical were investigated in detail. The principles of metabolism and co-metabolism, and the influences of objective factors such as temperature, pH, sludge retention time, dissolved oxygen and the chemical structure on the biodegradation modes and degradation processes were elaborated. The important role that the microorganisms and relevant enzymes played in the degradation was analyzed, and the mechanisms that the autotrophs degrade the chemicals via co-metabolism, while the heterotrophs via cometabolism and/or metabolism were elaborated. Finally, it was proposed that inherent biodegradability should be enhanced by adding growth substrate, controlling the microbial structure and mixed cultivating fungal laccase and microbial.