The morphology of irradiated high density polyethylene (HDPE) was observed with electron microscope and the relationship between morphology and radiation dose is analyzed quantitatively with statistical procedure.It has been found that the lamellar morphology of irradiated polyethylene did not change with changing radiation dose. If the HDPE samples irradiated at room temperature were melted and then recrystallized at 125±0.1℃ for 4 hours

the thickness of crystalline lamellae and the long period are reduced as compared with those without recrystallization. The results mentioned above are in good agreement with those obtained from SAXS exper-iments. They confirmed the "lamellar core damage mechanism" model.