Antheraea pernyi silk fibroin nanofibers were prepared from aqueous solution with electrospinning. The viscosity and conductivity values of the A. pernyi silk fibroin aqueous solutions with different concentrations were measured, and the morphologies of the prepared electrospun nanofibers were observed by scanning electron microscopy. The morphologies of the electrospun nanofibers changed from beadlike to uniform cylindrical and then to beltlike. The A. pernyi silk fibroin aqueous solution with a concentration of 31% exhibited good spinnability, in which uniform and regular nanofibers with an average diameter of 422 nm were obtained. The secondary structure of the electrospun A. pernyi silk fibroin nanofibers was studied by solid C-13-NMR cross-polarization/magic angle spinning spectroscopy, X-ray diffraction, and differential scanning calorimetry. The as-spun A. pernyi silk fibroin nanofibers presented a complete alpha-helix/random coil structure, and no beta-sheet structure was observed. After insoluble treatment with water vapor, alpha-helix and beta-sheet conformations coexisted in the A. pernyi silk fibroin nanofibers, and the beta-sheet conformation was predominant. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128:1081-1088, 2013