Alumina borate nanofibers were fabricated by electrospinning combined with sol-gel method using aluminum acetate (Al(OH)(2)(OOCCH3).1/3H(3)BO(3), stabilized with boric acid) and polyvinyl pyrrolidone (PVP) as raw materials. As-spun composite nanofibers were electrospun from the spinning solutions prepared with different PVP contents. The as-spun nanofibers were calcined at 1000 degrees C and the microstructures of the calcined nanofibers were investigated. The results showed that with the content of PVP increased, the diameters of the alumina borate nanofibers increased, and the temperatures at which the Al4B2O9 phase formed and Al4B2O9 transformed to Al18B4O33 also increased. However, the crystallinity of the calcined nanofibers decreased with the increase of the PVP content. The grains became smaller and more uniform due to the increasing amount of voids and cracks generated by the decomposition of PVP.