Abstract： Objective To observe the preventive effect of epidural injection with low - dose of ketamine on postanesthesia shivering(PAS) undergoing percutaneous nephrolithotomy. Methods Sixty ASA Ⅰ～Ⅱ grade patients aged 35 ～ 72 years undergoing PCNL were randomly divided into kctamine group (n = 30, Epidural injection of 0.5mg/kg of ketamine) ,Control group(n = 30, Epidural injection of 10ml saline). The rate of shivering was observed and recorded during operation,and blood pressure and respiration were measured. Results The rate of shivering in ketamine group(10%) was significantly lower than that in control group(46.7%, P ＜ 0.05) ,There were no significant differences of blood pressure and respiration between two groups (P ＞ 0.05). Conclusion Epidural injection 0.5 mg/kg of ketamine on postanesthesia can prevent shivering in PCNL.