Objective To investigate the effects of high mechanical index contrast-enhanced ultrasound on the proliferation and apoptosis of colonic cancer cells.Methods Lovo eell were cultured in vitro,and this study was divided into control group,simple contrast agent group,microbubble plus ultrasound radiation group and simple ultrasound radiation group.Contrast agent SonoVue and uhransound(frequency 1.5 MHz and MI 1.7)were used.Proliferation of Lovo cells were detected by MTT assay,and apoptotic index by flowcytometry(FCM),respectively.Results There weren't obvious differences in proliferation,apoptosis and cells cycle between the control group,the simple ultrasound radiation group and the simple contrast agent group(P>0.05).There were obvious differences between the control group and the microbubble plus ultrasound radiation group in proliferation ability and apoptotic index(P<0.01).Conclusions High mechanical index ultrasound radiation can enhance the contrast agent SonoVue's destruction,inhibit the proliferation and promote apoptosis of tumor cells.