Abstract: Silk fibroin(SF) and gelatin were dissolved in formic acid with different mass concentrations and the resulting spinning solution was electrospun into hybrid nanofibers whose morphology was observed by using SEM.The influence of technical parameters on the morphology and diameter of the hybrid nanofibers was investigated and a comparison was made between the hybrid nanofibers and pure SF nanofibers electrospun under the same process conditions.The results showed that hybrid nanofibers have an average diameter of(83.9 nm) and even distribution of fiber diameter when the proportion of SF to gelatin is(70∶30,) mass concentration of the spinning solution is 11%,polar distance is(13 cm,) and voltage is(22 kV.) The application of gelatin in the hybrid spinning solution is beneficial to solving such problems as breaking of fiber and beads appeared on fiber surface which are accompanied with electrospinning of SF spinning solution with low mass concentration.It will probably be applied in bioengineering.