Abstract: By mimicking the dryspinning process of silkworm, regenerated silk fibroin (RSF) fiber was dryspun and then posttreated to improve its mechanical properties. Compared to inorganic salt solution, the alcoholwater systems can obviously induce the conformation of the fiber from random coil and αhelix to βsheet. Meanwhile, a drawing induced orientation of βsheet can result in a drastic improvement of the fiber tenacity. The breaking strength and the elongation at break of the fiber are improved up to 200 MPa and 48%, respectively, when the fiber is drawn 2 times in ethanol aqueous solution (φ=80%), and then is immersed in the solution for 1 h.