In our study,metabolomics was used to investigate biochemical changes in the early stages of rats focal cerebral ischemia reperfusion(I/R) injury.Cerebrospinal fluid (CSF) samples of 0,0.5,1,3,and 6h of reperfusion(n=10),based on 1H NMR spectroscopy and multivariate data analyses,were tested to analyze the changing of metabolites during the early disease process.Partial least squares-discriminant analysis scores plots of the 1H NMR data revealed clear differences among the experiment groups.Combination the results of loading plot and t-test,we found that twenty-seven metabolites were changed significantly (p<0.05) in the CSF samples among the different groups.