Abstract: Objective To explore the expression of receptor tyrosine kinase EphB3 in normal fallopian tube， ovarian serous benign tumor and ovarian serous carcinoma， and its relation to clinical pathological parameters of ovarian serous carcinoma. Methods Nine cases of normal fallopian tubes， 12 cases of benign tumors and 53 cases of ovarian serous carcinomas were collected. All tissues were buffered formalin fixed and paraffin embedded. EnVision immunohistochemistry was used to detect the expression of EphB3. The relationship between expression of EphB3 and clinical pathological parameters was analyzed. Results EphB3 was highly expressed in normal fallopian tube （100.0％） and benign tumor （75.0％） and reduced expression in ovarian serous carcinoma （18.9％） with statistical difference（P＜0.001）. Expression of EphB3 was negatively associated with tumor grade（r=-0.606， P＜0.001）and FIGO stage （r=-0.463， P＜0.001）， and was not related to age， metastasis of greater omentum， metastasis of peritoneal cavity and lymph node metastasis of pelvic cavity. Conclusion EphB3 may be used to distinguish low and high grade tumor， and benefit for diagnosis and therapy of ovarian carcinoma.