Objective: To determine the clinicopathologic features, histological origin, diagnosis and differential diagnosis of pregnancy luteoma in the ovary. Methods: Clinical characteristics, pathological morphology, immunohistochemical staining, and reticular fiber staining in 10 cases of pregnancy luteoma were analyzed, and literature was reviewed. Results: Ten patients were all primiparas with no pregnancy history. The sizes of pregnancy luteoma were 3-10 cm with a soft buiging appearance. Most lesions were brown but a few were black or yellow. The characteristic feature was a diffuse growth of cells with conspicuous eosinophilic cytoplasm. Immunohistochemical results showed that the expressions of α-inhibin, AEI/AE3, CD99, and Vimentin were positive, while epithelial membrane antigen (EMA), S-100, HMB45, and MelanA were negative. Reticular fiber staining displayed that positive staining was around the cell nests of the tumor. Conclusion: Pregnancy luteoma is a rare tumor-like lesion in the late pregnancy. The gross appearance, immunohistochemical staining, and reticular fiber staining are helpful to the diagnosis of pregnancy luteoma which should be distinguished from the steroid cell tumor, corpus luteum of pregnancy, and metastatic malignant melanoma.