The Arg-Gly-Asp (RGD) sequence is one of the most effective cellular adhesion ligands and has been used to improve cellular activity of biomaterials for tissue regenerative medicine. The aim of this study was to develop new facile immobilization methods of RGD on electrospun polyurethane (PU) meshes, using tyrosinase (Ty), to promote attachment and proliferation of human umbilical vein endothelial cells (HUVECs). The RGD peptides were readily immobilized on PU substrates, for 1 h, using 0.4 kU/mL of Ty. Water contact angles and X-ray photoelectron spectroscopy (XPS) were used in order to verify that the RGD peptide was effectively conjugated onto the PU (0.120 nmol/mg-mesh); surface concentration was shown to be proportional to the peptide feed concentration. Enhanced HUVEC attachment onto the polymer substrate was observed after 1 day, and the immobilized RGD was clearly demonstrated to promote the proliferation and spreading of cells on the surface, indicating that the method developed for the conjugation of the peptides on the PU was efficient. These results suggest that this enzyme-triggered immobilization method for the cellular adhesion ligand, RGD, onto the PU mashes may be an efficient tool for improving the biological activity of substrates, especially for vascular tissue engineering.