Aim To investigate the mechanisms in protecting HUVEC against ischemia/reperfusion(I/R) injury directed by curcumin.Methods Hypoxia/reoxgenation(H/R) model was established on HUVEC.MTT colorimetric assay was used to observe the injury degree of hypoxia and reoxygenation at the different time.With preconditioning by different concentration of Cur,the survival rate of HUVEC subjected to H/R was assessed by MTT colorimetric assay.Pretreated with Cur(5 ?mol?L-1),the expression of LC3,cathepsin B,cathepsin L,Bax and Bcl-2 were observed by fluorescent staining and Western blot in HUVEC during H/R process.Results Cur(1.25~5 ?mol?L-1) played a protective role during H/R in HUVEC in a dose-dependent manner.During H/R,the expressions of LC3,cathepsin B and the ratio of Bax/Bcl-2 increased,and the nuclear translocation of cathepsin L was induced;when cur was pretreated,LC3 was furtherstrengthened,at the same time,the up-regulation of cathepsin B,the ratio of Bax/Bcl-2 and the nuclei-location of cathepsin L were inhibited partly by Cur.Conclusions Cur can raise the survival rate of HUVEC in the process of H/R.Cur increases the autophagy activity,depresses cathepsins and Bax/Bcl-2 to protect the endothelial cells.