Postoperative renal function recovery is very important to value the operation quality after kidney transplantation. Dexmedetomidine is a selective alpha-2 agonist,enhances urine flow rate and perioperative renal function. Some animal experiments have revealed its beneficial effects against ischemia-reperfusion injury (IRI), our goal is therefore to investigate the effectiveness of a recipient treatment with Dexmedetomidine during operation at reducing Cystatin C level and enhancing renal function after kidney transplantation.

Participants will be randomly assigned, in a 1:1 ratio, to receive Dexmedetomidine or control (0.9 %Sodium Chloride Solution,0.9%NaCl). The randomization sequence will be computer-generated, and randomization will be performed in blocks and will be stratified according to participating center.Dexmedetomidine and 0.9 %NaCl solution will be treated from 10 minutes before anesthesia induction, ending in the last 10 minutes before the operation to complete. Cystatin C level and urine volume (but are not limited to these data) at 1,7,14 days after the transplantation will be recorded. The participation of each patient is scheduled for 14 days.Investigators will research both living and cadaveric kidney transplants.

Inclusion Criteria:

Patients underwent renal transplant in the First Affiliated Hospital of Xi'an Jiaotong University.

Exclusion Criteria:

severe comorbidity history: severe cardiac dysfunction, central nervous system disease, endocrine, and history of mental disorders; alcoholic and long-term use of sedatives and opioids history; drug allergy history.