Objective: To investigate ultrasonic features of ovarian cystadenofibroma (CAF) and adenofibroma (AF). Methods: Ultrasonic features of 50 cases with ovarian CAF and 7 cases with AF were analyzed, and diagnostic performance of ultrasound was evaluated. Results: According to pathological findings of the CAF cases studied, 46 were benign CAF with 47 tumors identified, and 4 cases were borderline AF. All the seven AF cases were benign with single lesion. Pathologically, most of lesions was serous (53/58, 91.4%). With borderline CAF defined as malignant, the ultrasound differentiated benign from malignant masses of CAF and AF with a sensitivity of 100.0% (95%CI 39.8%-100.0%), specificity of 72.2% (95%CI 58.4%-83.5%), and accuracy of 74.1%. Most benign CAF masses were described as unilocular solid cysts (25/47, 53.2%) with regular morphology (43/47, 91.5%) and well-defined boundaries (46/47, 97.9%). Regular papillary projections (32/47, 68.1%) in CAF lesions manifested no or minimal color Doppler signals（31/32, 96.9%）. The borderline CAF masses were all identified with solid components or papillary projections, which manifested various degree of blood supply. Compared with benign CAF, borderline CAF showed more solid or papillary components [maximum diameter, borderline CAF was 19.5 (18.8-26.3) mm versus benign 8.0 (7.0-13) mm, P=0.002], with higher the maximum diameter ratio of the solid components or papillary projections to the mass [the borderline CAF was 0.35 versus benign CAF 0.15, P=0.033], and there were more blood supply inside the borderline CAF (4/4) than benign CAF (10/35), (P=0.012). Most of the AF masses were described as regular (6/7), well-defined (5/7) solid masses with shadowing identified (4/7). Absent color Doppler signals were recorded in the solid components (6/6). Conclusions: The ultrasound has a sound diagnostic performance for CAF and AF. Benign CAF lesions are mostly described as solid cysts with papillary projection(s) manifesting no or minimal color Doppler signals; borderline CAFs are mostly described as masses with papillary projection(s) and solid component(s) containing varied blood supply. AFs are mostly described as solid masses with shadowing identified and absent color Doppler signals. It is difficult to discriminate benign from borderline CAF, presence of solid components or papillary projections and copious blood supply may indicate borderline CAF.