Abstract: Abstract Objective： To observe the effect of creatine phosphate on cerebral infarction volume in focal cerebral ischemia/reperfusion rat model．Methods: Rats model of focal cerebral ischemia/reperfusion injury were randomly divided into 5 groups：groupⅠ,shame operation, groupⅡ,ischemia/reperfusion injury (I/R); groupⅢ,low dosage of creatine phosphate 20mg/kg（L）; groupⅣ, medium dosage of creatine phosphate 40mg/kg (M); groupⅤ,high dosage 80mg/kg（H）; The activity of SOD、MPO 、MDA and Na+-K+-ATP enzyme were measured at the end of reperfusion. Infarction conditions and volume of cerebral was determined by dyeing with hematoxylin eosin (HE) and triphenyltetrazolium staining at the end of reperfusion. Results ：As far as the activity of MDA、SOD、MPO and Na+-K+-ATP enzyme, there are great significant differences among five groups at the end of reperfusion（P<0.05）. There is also great significant difference of infarction volume between group Ⅲ and groupⅣ（P<0.05）.Conclusion: pre-conditioning of creatine phosphate can attenuate ischemia/reperfusion injury of focal cerebral.

Key words: creatine phosphate sodium, cerebral, infarction volume , ischemia /reperfusion injury