Objective To evaluate antiangiogenic therapeutics effect with contrast-enhanced gray-scale ultrasound.Methods Kun-min mouse with subcutaneously implanted H22 mice hepatoma were treated with thalidomide or placebo by oral gavage over 7 days, starting at clay 2 post-implantation.Contrast-enhanced gray-scale ultrasound was performed on day 8.The tumor maximum cross-sectional area and non-enhanced area in ultrasound imaging were measured on the ultrasound machine.The percent of non-enhanced area from contrast-enhanced gray-scale ultrasound was calculated.Immediately after imaging, minces were euthanized and tumor tissue removed for fixation in a 10% formalin solution.The section equivalent to ultrasound imaging plane was stained with Hematoxylin and Eosin(HE) to allow for assessment of maximum cross-section area and necrotic area.The percent of necrotic area from HE stained section was calculated.Results The difference of maximum cross-sectional area measured in ultrasound and pathology slice was not significant between control and treated tumors (P >0.05).Ultrasound measurement of the tumor non-enhanced area and the percent of non-enhanced area were significantly larger in treated tumors than in control tumors (P <0.001).The necrotic area and the percent of necrotic area measured from HE stained section were also significantly larger in treated tumors than in control tumors (P < 0.001).The maximum cross-sectional area determined by the two methods was well corrected (r = 0.815, P < 0.001).There was good correlation between the non-enhanced area in contrast-enhanced gray-scale ultrasound and the necrotic area in pathology slides (r = 0.909, P <0.001).The percent of non - enhanced area calculated from ultrasound highly correlated with necrotic area estimated by pathology slides (r = 0.910, P <0.001).Conclusions Contrast-enhanced gray-scale ultrasound can detect the intratumoral necrosis and changes of tumor perfusion caused by antiangiogenic treatment before apparent change in tumor volume.