Aim This paper studies the effect of ERK1/2 signal transduction in focal acute brain ischemia-reperfusion.Methods 36 healthy male SD rats were randomly divided into sham operation group and ischemia group. Ischemia group was further divided into brain ischemia-reperfusion with differernt time (6, 12, 24, 48 and 72 h). Suture-occluded method was used to build cerebral middle artery infarction model (MCAO). CD34, Ang-2 and ERK1/2 were detected through immunohistochemical method.Results Ang-2 and ERK1/2 in focal cerebral ischemia-reperfusion rat model had dynamic change, and both reached peak at 24 hour.Conclusion ERK1/2 signal transduction way takes part in the promotion effect of angiogenesis of angiopoietin.