Objection:Serving the effects of shenfu pre-injection on hemodynamics in patients undergoing single spinal anesthesia. Methods:ninety patients who scheduled for abdominal or lower limb operation were randomly divided into two groups with 45 cases each group.Group A were injected 50ml Shenfu dissolved in 500mL Sodium dissolved in 500mL sodium lactate ringer injection before anesthesia.And group B were only injected 500mL sodium lactate ringer injection.The following data were recorded and analyzed:SBP、 DBP、 HR、 SPO2 and the cases of using ephedrine and atropine.Results:Compared with group B，SBP and DBP were obviously increased in 5 minutes and 10 minutes after anesthesia in group A(P＜005)；HR was obviously increased in 15 minutes(P＜005).The cases of using ephedrine and atropine were obviously decreased in group A(P＜005)than group B.Conclusion:Pre-injection shenfu is useful in maintaining stability of hemodynamic in patients during single spinal anesthesia，which could decrease the incidence of hypotension and bradycardia.