Abstract: A bacterium，isolated from putrified poly(vinyl alcohol)(PVA) gum，could degrade completely poly（vinyl alcohol）.It belongs to the genus of Xanthomonas and needs complex organic nitrogen for growth.The biodegradation rate of PVA was increased by addition of beef extract and peptone F403，in which peptone had more influence on PVA degradation.The bacterium could adapt to a broad pH range for PVA degradation.The polymerization degree of PVA did not show any significant influence on PVA biodegradation rate.The results of resting cells culture showed that PVA was firstly adsorbed and then degraded by the cells.1 g•L^-1 of PVA could be completely degraded as expressed with TOC by 1 g•L^-1 of resting cells after 52 h cultivation.However it was difficult to determine the activity values of PVA oxidase，dehydrogenase and total degrading enzyme in this strain.