Abstract: The radiation effect of γ-ray and electron beam on polyether-urethane was discussed. The thermal property and radical intensity were determined by differential thermal gravimetric analysis and electron spin resonance. The composition and content of gas products from samples irradiated by different ionizing radiation were analyzed by gas chromatography. The action mechanisms of these two radiation resources of γ-ray and electron beam are same, but the means of energy deposit is different. It results in the difference of radical intensity, the thermal property of polyether-urethane and its gas products from the radiation decomposition.