To investigate the function，function regulation and structure-function relationship of endothelial nitric oxide synthase(eNOS)，a gene fragment encoding eNOS 801～902 AA residues was cloned by PCR, and inserted into pET-28a(+) expressive vector. The resulted pET-28a/eNOS₂ was transformed into BL₂₁ host E.coli and expressed by IPTG induction for 4 hour, The expressed protein (14.4 ku) was purified by His-Bind^TM Sephorose colum and SDS-PAGE, thus providing the basis for the selection of the eNOS-specific inhibiting peptides and the preparation of the specific antibody against eNOS.