By means of the anaerobic technique,using mushroom residues as raw materials to elucidate the relationship between the functional bacteria distribution and biogas production rate during the biogas fermentation Was studied. It is found that in the first stage of the fermentation process, the acid-producing bacteria dominate the digest system, wheras the major microbes in the second(middel) stage are cellulolytic bacteria, and in the last stage, the number of methane-producing bacteria is slightly higher than in the first stage. In view of methane production the mushroom residues may be better than rice-strow as raw materials for biogas fermentation.