Abstract: Objective To study the characteristics of renal blood flow with contrast ultrasound. Methods The examination of the renal ultrasonography was performed in 10 dogs after intravenous injection of Quanfuxian (a contrast agent consisting of C3F8 microbubbles). Results Contrast visualization appeared in the renal cortex and then in the outer to inner medulla at the baseline level after administration of the contrast agent. Notable differences in the values of microvascular volume (A, which was 120.3 in the corted vs 110.8 in the medulla, P>0.05), microcirculatory flow velocity (β, which was 1.39 in the corted vs 0.54 in the medulla, P<0.05), and microcirculatory flow rate (A×β, 167.4 in the corted vs 59.5 in the medulla, P<0.05) were found between the corted and the medulla, with also marked difference between the the corted-to-the medulla ratios of β and A (0.612 vs 0.078, P<0.05). Conclusion Contrast ultrasound of the kidney provides a useful means of renal circulatory flow study.