Abstract: Objective To study the ultrastructural changes of pulmonary gland cancer cell line Anip973 after 6 MV X-ray irradiating with different doses. Methods Lung gland cancer cell line Anip973 were radiated by 6 MV-X ray with 10 and 20 Gy in single fraction. The ultrastructural changes of cellular damage were observed by transmission electron microscope after 24 h and 48 h. Results Cells of the control group grew actively with vigorous metabolism. In 10 Gy group, reversible cell swelled after 24 h and obvious apoptosis occurred after 48 h. In 20 Gy group, cellular swelling and apoptosis both existed after 24 h. Oncosis was the main style for cell death with typical and wide dissolved necrosis after 48 h. Conclusion Oncosis is the main style of cell death with high dose radiation in single fraction. Typical dissolved necrosis appears after irradiation for 48 h.