Abstract: Objective：To study the effect of X-irradiation to the morphology and function of the ovary of mice. Methods：The test is grouped by the dose：0，0.2，0.4，0.6，0.8，1.0 Gy. Use HE stain to observe the number of the every grade follicles，immunohistochemical technique to observe the expression of the P53 protein and Bcl-2 protein，TUNEL technique to observe the expression of the apoptotic bodies. Results：With increasing of the dose of X-ray ionizing radiation，the number of the primordial follicles，the primary follicles and the secondary follicles reduces（P＜0.01），the most prominent is primordial follicles，but the antral follicles don’t change significantly（P＞0.05）. When the absorbed dose is 0.2 Gy，the expression of P53 protein and apoptotic bodies in ovarian granulosa cells is lower，however the expression of Bcl-2 protein levels is higher（P＜0.01）. But when absorbed dose is from 0.4 to 1.0 Gy，with increasing of dosage，the expression level of P53 protein and apoptotic bodies in ovarian granulosa cells increase，and the expression level of Bcl-2 protein deseases（P＜0.01）. Conclusions：X-irradiation can reduce the number of the primordial follicles，advance the apoptisis，then affect the regulation of gonadal hormone secretion.

Key words: X-ray, Radiation, ionizing, Ovary, Tumor suppressor protein p53, Proton-oncogene c-bcl-2