【】 Objective To investigate the clinical features and ultrasound manifestations of aovarian endometrioid carcinoma(OEC) in order to improve the recognize and the ability of ultrasound diagnosis of OEC. Methods The clinical and ultrasonic data of 18 patients with OEC confirmed by pathology in our hospital were retrospectively analyzed, and the clinical features and ultrasound characteristics of OEC were summarized. Results? Among 18 patients of OEC,17 were unilateral and 1 was bilateral,and 8 of these patients also had a synchronous endometrial cancer,the median age was 48 (range 24-59) years and 5 patients were nulliparous and 13 patients were premenopausal;there were 10 of serum CA125、CA19-9 and HE4 were elevated simultaneously；pelvic or lymph node metastasis in 4 cases.The masses median largest diameter was 113 (range 34-233)mm,18 of them were mixed cystic-solid and the other one was solid,13 masses with clear boundary and 6 others appeared boundary ambiguity,the shape regular and irregular has 5 cases and 14 cases respectively, the blood flow was abundant and a little has 15 cases and 4 cases respectively;in addition,among 18 masses of mixed cystic-solid,there were 9 cases with thickening and uneven thickness,8 cases with rough wall and 1 case with smooth wall,16 cases cystic with low-weak echo and the 2 others has clear echo,inside the cyst has 9 bands with uneven thickness, 7 with even thickness and 2 without septa,all of the solid part of the mixed cystic-solid masses