Prepolymer of arylacetylene and Polyarylacetylene (PAA) were irradiated by 60Co γ-rays to investigate the effect of irradiation on their properties. DSC and TGA were applied to study the thermal polymerization process of prepolymer of arylacetylene and the performance of PAA. The results show as follows: (1) The curing enthalpy of prepolymer of arylacetylene irradiated by 60Co γ-rays is depressed; (2) The thermal stability of pre-irradiation thermal polymerizated PAA is better than directly thermally polymerized PAA; (3) The thermal performance of PAA can be improved by post-irradiation treatment. It is deduced that the thermal performance of PAA can be effectively improved by 60Co irradiation.Cited