Abstract: In this paper,we wi11 describe PA spectrum of carbon fiber and its composite materials for example,PAN,GF-PPS,CF-PEEK,CF-epoxy resin etc,by STIR-PAS technique.We make some experiments for SAN for fiber with different oxidation degree and find that the intensity of C-H staectching band at 2920 cm^-1 and C≡N stiectchiag liarid at 2250 cm^-1 decreases as the degree of oxidation of preoxidized PAN fiber increases.Experimental resuIfs shown good agreement with elenentary analysis.We also study PA spectrum of CF-epoxy resins before and after oxidation and find satisfaction in the results of study.