Thermal decomposition mechanism and kinectics of α=cellulose on Grafting of Acrylonitrile onto partially α-Cellulose were obtained using thermal analysis, pyrolysis gas chromatography and fourier transform-infrared spectrometer method under dynamic and isothermal conditon in the stream of nitrogen. 1. the values of activation energy evaluated by Friedman's and Ozawa's method were consistent with each other very well. It was possible to determine the thermal stability of samples from these results. 2. the optimum thermal stabilization in Acrylonitrile-grafted α-cellulose was obtained in composition of 5 ~ 10% AN.