Using a differential scanning calorimeter（DSC）,an experiment was conducted to determine how the curing process for UF resin could be influenced by adding NH,4,Cl as a curing agent and various ratios of cotton-stalk to poplar fiber.Results showed that as the addition of NH,4,Cl increased,up to a maximum of 1.5%（based on UF resin）,the curing rate of UF resin continued to increase.The ratio of cotton stalk to poplar had less effect on the initial curing process for UF resin.However,as the curing process went on,the decomposition of the methylene-ether linkages to methylene-bridges increased.When the ratio of cotton-stalk to poplar was 4∶0,the reaction rate was the highest;followed by 3∶1,0∶4,1∶3,and the lowest was 1∶1.