〔Abstract〕 Objective To analyze the expression and clinical significance of OCT4 in normal ovarian tissues, ovarian dysgerminoma, immature and mature teratomas. Methods A total of 67 samples of ovarian primordial germ cell tumors (including 11 cases of immature teratoma, 16 cases of mature teratoma and 40 cases of ovarian dysgerminoma) were collected from Fuzhou Kingmed for Clinical Laboratory from January 2017 to January 2022. The expression of OCT4 in ovarian primordial germ cell tumors and 25 cases of normal ovarian tissues was detected by immunohistochemical streptavidin-peroxidase (SP) method. The relationship between OCT4 expression and clinicopathological features and prognosis of ovarian dysgerminoma was further analyzed. Results The positive rate of OCT4 in dysgerminoma was significantly higher than that in normal ovarian tissues, immature teratoma and mature teratoma tissues, the difference was statistically significant (P < 0.05). The expression of OCT4 in patients with ovarian dysgerminoma was closely related to tumor diameter, peritoneal effusion volume, pathological stage and lymph node metastasis, and the difference between positive (++) and strongly positive (+++) was statistically significant (P < 0.05). The expression of OCT4 was not related to age and tumor side, and there was no significant difference between positive (++) and strongly positive (+++) (P > 0.05). Log-rank test results showed that the survival rate of patients with high OCT4 expression was significantly lower than that of patients with low OCT4 expression (P < 0.05). Conclusion OCT4 is not expressed in normal ovarian tissues, immature teratoma and mature teratoma tissues, but positively expressed in ovarian dysgerminoma tissues. It may be involved in the pathological process of ovarian dysgerminoma. Detection of OCT4 expression is helpful for the clinical diagnosis and prognosis evaluation of ovarian dysgerminoma.