Abstract: The electrospinning of regenerated silk fibroin(SF) and gelatin blended with the composition ratio 70∶30 was performed with 98% formic acid as spinning solvent.The influence of mass concentration and ethanol treatment on the microstructure,mechanical properties and solubility of electrospun SF/gelatin nanofibers was investigated.The pore diameter and porosity of SF/gelatin fiber membrane with different mass concentrations and different thickness were measured.The mouse fibroblasts and human umbilic vein endothelium cells were seed on SF/gelatin nanofibers scaffold.The results showed that: along with the mass concentrations of spinning solution increasing and ethanol treating,the content of β-sheet of SF in electrospun SF/gelatin nanofibers was increased,crystallinity increased,water-dissolved rate declined,and tensile strength enhanced of electrospun SF/gelatin nanofibers;as the mass concentration of spinning solution increased,the pore diameter of electrospun SF/gelatin nanofibers was decreased and the porosity was increased;both the pore diameter and porosity were decreased with the increase of the thickness of electrospun SF/gelatin nanofibers.The SF/gelatin nanofibers scaffold may be a good candidate for both L929 and HUVECs spreading and proliferating.