Thermoluminescence(TL) properties of high strength homopolymer polyacrylonitrile (PAN) fibers were studied to compare those of other ordinary homo- and acrylonitrile(AN) /metbylacrylate(MA) copolymer PAN fibers. The TL properties of PAN fibers was much stronger than in other polymers due to thermo-oxidation induced during heating in TL measurement. That is, thermo-oxidation begins at about 80˚C and remarkably increases with increasing temperature. In this study, the true TL intensity due to detrapping of the second electrons ejected by X-ray exposure was separated from that due to oxidation. The true TL intensity was much smaller in homopolymer PAN fibers than for copolymer PAN fibers. It was suggested that molecular heterogeneity due to copolymerization increases the number of electron trap-sites not only in the amorphous phase but in other phases. Although the difference of TL glowability between high strength and ordinary homopolymer PAN fibers was much smaller than that expected from the difference in fine structure, there was still some difference in the profiles (shape of TL- temperature curves). The TL- and mechanical tan $delta$-temperature profiles have a high correlation. Homopolymer fibers have smaller intensities for both TL and tan $delta$ than copolymer fibers.