Abstract: Objective To investigate the diagnostic value of ultrasound cardiography (UCG) in cardiac tumor. Methods Twentyfive patients with primary cardiac tumor detected by echocardiography in our hospital from January 2007 to June 2017 were enrolled in this study, and their ultrasonographic characteristics and surgical pathologic results were analyzed. Results There were 12 males and 13 females aged from 22 to 77 years with average age of (50.4±11.99) years. According to the lesion location, border, shape, utralsonic image and mobility of the areas invaded by tumor, benign myxoma was diagnosed in 16 cases preoperatively, which were consistent with surgical pathological results with accuracy of 100%. However, there were 7 cases whose pathologic types could not be determined by ultrasound examination (28%, 7/25). Of the 7 cases, we speculated that 5 cases were with benign tumors and 2 cases with malignant tumor, but all their postoperative pathological results proved to be benign. Two cases diagnosed as malignant by UCG, being consistent with postoperative pathological results. UCG showed the tumor size ranged from 10 mm×10 mm in minimum to 120 mm×150 mm in maximum. All cases were definitively diagnosed by surgical pathologic results in our hospital's cardiothoracic surgery department, including 23 cases of primary cardiac benign tumor (92.0%) and 2 cases of malignant tumor(8.0%). During early postoperative recovery, 23 patients recovered very well, whereas the other two died of low cardiac output syndrome. Conclusion UCG can make qualitative diagnosis to atrial myxoma. Atrial myxoma that involves right heart system and combines with hydropericardium is more likely to be malignant. Echocardiography is hard to make precise pathological diagnosis for cardiac tumor except myxoma.