Objective:To evaluate the characteristics of contrast-enhanced ultrasonography in renal VX2 tumors.Methods: VX2 tumors were transplanted into 12 rabbit kidneys and observations were made by contrast-enhanced ultrasonography 7,14 and 21 days after the transplantation respectively.Results: The best intervention time was 2-3 weeks after the tumor transplantation,while nicrosis was apt to occur after 3 weeks.The visibility of the renal tumors was significantly increased from 57.1%(12/21) to 100%(21/21).Contrast-enhanced ultrasonography showed defect and delineation of VX2 tumors. Conclusion: Contrast-enhanced ultrasonography can improve the peripheral and internal blood flows of the tumors promote the diagnosis of renal tumors.