A group of Poly(vinyl alcohol) (PVA)-degrading bacteria， Bacillus sp. and Curtobacterium sp.， were isolated from watercourse and sewage sludge of Sichuan Vinylon Works，and a PVA-degrading bacterial culture was obtained. The effect of molecular weight and degree of hydrolysis on the biodegradation of PVA was investigated in above culture by spectrophotometric analysis. The results show that: the bacteria and the culture based on it can be used to study the biodegradation of PVA; a rather significant degradation within quite short incubation times was been observed; the molecular weight and degree of hydrolysis of PVA appeared to be the factors of microbial attack. The analysis of the FT-IR and 1H-NMR spectrums of the PVA sample before and after biodegradation indicated a fission of PVA chain during the inoculation.