Continuous mullite nanofibers with highly aligned structure were fabricated by conjugate electrospinning technique combined with the sol-gel method. Aluminum acetate stabilized with boric acid and tetraethyl orthosilicate (TEOS) were used as raw materials. Aligned and continuous as-spun nanofibers were prepared first. After calcining at 1000 degrees C, the obtained mullite nanofibers retained decent alignment and continuous structure despite the decomposition of PVP and other organics. Such fibers were composed of Al4B2O9 phase and amorphous SiO2. The elastic modulus of a single mullite nanofiber was 12.27 +/- 1.77 GPa and the tensile strength of the aligned mullite nanofiber bundle was 32.21 +/- 3.73 MPa. (C) 2017 Elsevier B.V. All rights reserved.