Objective To analyze the clinicopathologic features of ovarian serous borderline tumors and to discuss its diagnosis and differential diagnosis.Methods Fifty-seven cases of ovarian serous borderline tumors di-agnosed in the Department of Pathology of the first affiliated hospital of Xiamen university were retrospectively an-alyzed.The immunophenotypes were analyzed and the relevant literatures were reviewed.Results There were dif-ferences in the histopathologic morphology of NOS and micropapillary variant of ovarian serous borderline tumors,as well as in the incidence of bilateral ovaries with noninvasive implantation and microinfiltration.Conclusion It is important to distinguish between serous borderline neoplasms that are NOS and the micropapillary variant,which has a poorer prognosis than the NOS.