Abstract: Objective To investigate the effects of dexmedetomidine on renal microcirculatory perfusion in rabbits with renal ischemia/reperfusion (I/R) injury rabbit by quantitative analysis of contrast-enhanced ultrasound (CEUS). Methods Twentyfour New Zealand rabbits were randomly divided into 3 groups (8 in each), including a control group, renal I/R injury group and dexmedetomidine group. In the latter two groups, the right kidney of the rabbits was resected and I/R injury was induced in the left kidney. In dexmedetomidine group, the rabbits received an intraperitoneal dose of 10 μg/kg dexmedetomidine 30 min before renal ischemia, and 24 h after reperfusion, the renal size and renal artery resistance (RI) were measured, and renal cortex perfusion was observed by CEUS. The time-to-peak intensity (TTP), peak signal intensity (PSI), gradient between start frame to peak frame (Grad) and area under the curve (AUC) were quantitatively analyzed using the time-intensity curves. Pathological changes of the kidney were also observed. Results Compared with the control group, the rabbits in I/R and dexmedetomidine groups showed distinct changes of the renal size with obvious renal pathologies. RI, PPT and AUC all increased, and PSI and Grad decreased significantly in I/R and dexmedetomidine groups (P<0.05). Compared with I/R group, obvious improvement of the renal size and renal pathologies were observed in dexmedetomidine group, which showed significantly decreased RI, PPT and AUC and increased PSI and Grad (P<0.05). Conclusion CEUS combined with the time-intensity curve parameters allows quantitative and dynamic analysis of the protective effects of dexmedetomidine on microcirculatory perfusion in rabbits with renal I/R injury .