Abstract: Objective To investigate ultrasonic diagnosis of lower abdominal retroperitoneal neoplasm and its value for differential diagnosis of gynecological tumors. Methods Color doppler ultrasonography results and clinical data about 52 female patients with lower abdominal retroperitoneal neoplasm confirmed by surgery pathology in our hospital from January 2012 to March 2015 were retrospectively analyzed. Results According to the results of ultrasonic diagnosis, 47 cases were retroperitoneal neoplasm, 5 cases were gynecological tumors (among them 4 cases of suspected sources of ovaries, 1 case of suspected sources of uterus), with localization diagnosis coincidence rate of 90.4% (47/52). According to the postoperative pathology, 36 cases (69.2%) were malignant tumor, and 16 cases (30.8%) were benign tumor. In accordance with ultrasound diagnosis, 34 cases were conformed to be malignant tumor, 11 cases were conformed to be benign tumor, and the qualitative diagnosis coincidence rate was 86.5% (45/52). Conclusion The combination of mass ultrasonographic characteristics and clinic can effectively improve the lower abdominal ultrasound diagnostic accuracy rate of localization and qualitative of retroperitoneal neoplasm.