Abstract: Objective:To investigate the role of ultrasound guided percutaneous biopsy in diagnosis of greater omentum mass.Methods:The sonograms of greater omentum and the pathological results of the patients were analyzed.Results:The successful rate of biopsy was 100%.Forty-five of the 64 cases were proved to be benign greater omentum mass including 35 cases of tuberculosis,2 chronic infection,2 cystic lymphangioma,1 leiomyoma and 1 teratoma,4 cases presented no specific findings.Among the 19 cases of malignant greater omentum mass,leiomyosarcoma was found in 2 cases,liposarcoma in 1 case,malignant mesothelioma in 2 cases,and lymphoma in 1 case and metastasis tumor in 13 cases.Conclusions:Ultrasound guided percutaneous biopsy is of great help to the diagnosis of greater omentum mass,even when the ascites cytology is negative.