Abstract: Objective: To investigate the effect of rehabilitation with constraint-induced movement therapy(CIMT) at different times on neural function and observe the expression of nestin after middle cerebral artery occlusion in rat model.Methods: One hundred and sixty healthy male SD rats were randomly divided into 4 groups:normal group,sham operation group,model group and treatment group.The rats in each group were divided into 5 subgroups by 6 h,12 h,24 h,48 h and 72 h,8 rats in each group.The rats in treatment group were treated with rehabilitation with CIMT,while the rats in other groups were treated with normal feeding.The success rate of neurologic impairment scores was analyzed and the expression of nestin in cortical ischaemic lesion was observed by immuno-histochemical technique after 14 days.Results: After cerebral infarction for 6 to 72 h,the rats in normal and sham operation groups were no nerve defect performance at each time point,but the scores of nerve function defect in treatment group were lower than the scores in model group(P<0.05);there was no statistical significance of nerve function defect scores in model group and treatment group at 6 to 72 h interval time differently(P>0.05);the positive cell number of nestin in normal and sham operation groups was significantly less than that in model and treatment groups after cerebral infarction for 6 to 72 h(P<0.01),and the positive cell number in treatment group was significantly higher than that in other groups at different time points(P<0.01);there was no statistical significance of positive cell number at different time points among normal,sham operation and model groups(P>0.05);and the positive cell number of nestin after cerebral infarction for 24 h was higher than that at other time points in treatment group(P<0.05).Conclusions: The best time to do compulsory rehabilitation training was after cerebral infarction for 24 h in rat;the mechanism may be related to increase infarct peripheral nerve stem cell proliferation and differentiation.