The effects of electron beam irradiation on polyethylene foam of open cell type have been studied. Experiments for determining of gel fraction and physical-mechanical properties of irradiated polyethylene foam of open cell type as a functoin of dose, respectively, were carried out. The dimensional stability of irradiated specimens at elevated temperatures also was measured. It was found that tensile strength did not change and gel fraction increased when the specimen was irradiated in nitrogen atmosphere with increasing dose up to 300 kGy. The result shows that dimensional stability of polyethylene foam of open cell type after being kept in an oven at 70℃ and 110℃ for 22 h is improved by irradiation in nitrogen atmosphere. The similar results of irradiated EVA foam of open cell type to irradiated PE foam of open cell type were obtained.