Viable But Non-Culturable (VBNC) is a special state of bacteria for survival. It is a conventional state for bacteria innatural water body. Complicated environment factors may be the rational reason of the interchange. In this study, the effects ofcyanobacterial media and crude microcystin on the VBNC state of A. sobria were conducted by incubating Aeromonas sobria into asterile lake water. The results showed that some bacteria were in the VBNC state while others in culturable state;both cyanobacterialmedia and crude microcystin could improve the change of A sobria from VBNC state to culturable state. It revealed that microcystinmight be an important environmental factor involved in the VBNC state transfering in aquatic environment. More research concernedabout molecular mechanism was undergoing.