Heat shrinking material of γ-radiation erosslinked polyethylene is widely used for various application in industry. In this study, DSC, TMA, WAXD and density measurement techniques were used to investigate the influence of MI and thermal history of LDPE on the effectiveness of network formation. Based on the results of heat stretching and heat shrinkage tests, it is found that the formation of a network as perfect as possible is indispensable to the irradiated material if good heat shrinkage property is desired.To this end,quenching technique and polyethylene with appropriate MImust be used so that an effective radiation effect will be obtained with a minimum amount of radiation dose.In spite of that the mechanical property of the irradiated polyethylene in the rubbery state is basically in agreement with the classical expression of the theory of high elasticity,only about 90% shrinkage can be reached.Besides,the heat shrinkage temperature Ts and the % shrinkage S are both related to the radiation dose.