Morphological change of electrospun fiber with various solvent was conducted to figure out solvent effect on the surface of ethyl cellulose nanofiber. THF (bp 66 ℃) and DMAc (bp 165 ℃) binary solvent system was introduced and electrospinning was performed with different ratio of THF/DMAc including each pure solvent at 100 μL/min flow rate of 15 % (w/v) ethyl cellulose dissolved in the solvent. The applied voltage was 10, 13, 15, and 20 kV under 10 cm tip-to-collector distances. Morphology of fibers was evaluated by SEM image through the various magnification. Regular holes were formed on the surface of fiber from pure THF and 80 % THF in DMAc, while smooth surface was observed for the pure DMAc and 80 to 20 % DMAc ratio in THF. As the electric conductivity increased, the diameter of electrospun fiber decreased. In case of binary solvent, the average diameter decreased from 1100 to 500 nm as increased the ratio of DMAc from 20 to 80 %.