Small-diameter vascular grafts with the nitric oxide (NO) releasing property were designed and prepared. Diazeniumdiolated N,N'-dibutyl-1,6-hexanediamine (DBHD/N(2)O(2)) was first synthesized as the NO donor and doped into the biocompatible polymer poly(epsilon-caprolactone) (PCL). The fibrous vascular grafts were fabricated by electrospinning. Despite the reduced platelet adhesion observed on the NO releasing grafts, the cytotoxicity and burst release were apparent, especially at a higher loading level of the NO donor. In order to solve this problem, core-shell structured nanofibers, in which PCL or gelatin is the shell and PCL doped with the NO donor is the core, were fabricated via coaxial electrospinning. The core-shell structure made the NO release more steady and controllable, and the cell compatibility was improved.