Abstract: Objective To investigate Color Doppler flow imaging and Real-time Gray-scale Contrast-enhanced Ultrasound in the diagnosis of breast tumor.Method We used Color Doppler flow imaging and Real-time Gray-scale Contrast-enhanced Ultrasound in the diagnosis of 72 breast tumor before operation.We compared with pathology result,the characteristic of Color Doppler flow imaging and Real-time Gray-scale Contrast-enhanced Ultrasound in benign tumor and malignant tumor.Then,we compared sensibility,specificity and coincidence.Result 1.Breast tumor has different characteristic of Color Doppler flow imaging and Contrast enhanced Ultrasound.0~Ⅰgrade blood flow and RI＜0.7 was found in most benign tumor.Ⅱ~Ⅲ grade blood flow and RI≥0.7 was found in most malignant tumor.Most benign tumor was enhanced by equal.Even most malignant tumor was enhanced by high and uneven.2.Sensibility of Contrast-enhanced Ultrasound is 100%,obviously higher than that of Color Doppler flow imaging(79.2%).3.Sensibility,specificity and coincidence of Color Doppler flow imaging is 71.4%,80.0% and 75.0% with Kappa value 0.50,which were 76.2%,70.0% and 73.6%,respectirely referring Contrast-enhanced Ultrasound with Kappa value 0.46).Conclusion Real-time Gray-scale Contrast-enhanced Ultrasound has more specificity in blood flow of tumor,but its differential diagnosis capability doesn′t surpass Color Doppler flow imaging.