In this paper the experimental results measured continuously on the gaseous products of high temperature pyrolysis (300℃ to 960℃) of acrylonitrile polymers were described under given nitrogen atmosphere by on-line Fourier Transform Infrared Spec-troscopic method (FTIR). From the variations of intensity of characteristic peaks it was found that the nitrogen

of macromolecules evolved were mainly in the form of hydrogen cyanide and ammonia. During the pyrolysis amorphous carbonaceous element was formed

and crosslinked to form a network structure. Three samples were used for comparison. The experimental results show that the gaseous products of volatile small molecules were HCN

NH3

CH4

C2H6and cyanide

CO and CO2 were formed when co-polymer of PAN were thermally pyrolyzed.