Abstract: Objective: To investigate characteristic CT manifestations of the ovarian thecoma-fibroma and improve the level of preoperative diagnosis. Methods: Clinical data, CT manifestations and pathological features of 18 cases of ovarian thecoma-fibroma were analyzed retrospectively, and the diagnoses were confirmed by pathology after surgery. Results: Our findings included: 18 patients were all unilateral; 10 lesions were located in the left side of ovary, while 8 lesions were in the right side. Of the 18 lesions, the largest diameters of tumor ranged from 1.5 to 18mm with the mean value of 8.7mm. 13 patients were accompanied by ascites, of which 4 cases were combined with pleural effusion. The shape of 13 lesions appeared round or elliptic, and 1 lesion with lobulation, 4 lesions were irregular. All the tumors had well-defined or mostly well-defined borders. The tumors showed solid density in 7 cases, cystic solid density was observed in 11 cases. No enhancement was found in the cystic part after enhancement. The solid part of solid mass or cystic solid mass showed no obvious enhancement in the arterial phase after injection of the contrast medium, while in venous phase and delayed phase presented continuous and asymptotic slight enhancement. The CT value of the solid part increased by 2~18HU in the delayed phase after enhancement compared with plain CT scan, and did not exceed 20HU. Conclusions: The characteristic CT manifestations of the ovarian thecoma-fibroma were often unilateral solid mass with the shape of oval and well defined border; slight enhancement; accompanied by ascites.