The viscosity and the UV-vis spectrum of PVA degradation aqueous solutions, the FTIR, and DSC spectrums of degradation products were measured to investigate and compare the effect of Fenton's reagent and urea/H2O2 activate oxidation systems on the degradation of PVA. The results showed that the viscosity of PVA aqueous solution decreased and the degradation rate of PVA increased with the concentration of hydrogen peroxide in both activate oxidation systems. The FTIR and DSC spectrum of degradation products showed that the degradation products contained aldehyde, ketone groups. The aldehyde compounds and carbon dioxide produced in the degradation systems were validated by Fehling reagents and clarifying limewater. When the urea/H2O2 system was applied in the one-bath and one-step desizing and scouring process of polyester/cotton 65/35 Fabric, the results of 94.7% degradation rate of PVA, the 99.0% desizing rate of PVA, the whiteness, and wicking height of the fabric were obtained. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 860-867, 2009