Effects of ethanlo treatment on the structural and thermal characteristics of regenerated Antheraea pernyi silk fibroin (RSF) were investigated. Infrared spectroscopy and X-ray diffractometry showed that the conformational transition of RSF might be affected by concentration of ethanol and its treatment time. The structure of RSF was rapidly changed from random coil to $eta$-sheet conformation when RSF was treated with les than 75% ethanol concentration. However, RSF treated with ethanol(100%) did not show conformational change. Differential scanning calorimetry showed that exotherm at 232$^{C}$ disappeared and the intensity of endotherm at 228$^{C}$ decreased with treatment of 75% ethanol. Dynamic thermal analysis showed that loss modulus (E") and tan $delta$$\_$E/ of RSF treated with aqueous ethanol was broaden and shifted to higher temperature in comparison with those of untreated RSF.