Polyacrylonitrile (PAN)/silica composite nanofibers, in the diameter of 200-300 nm, were prepared by a one-step electrospinning method. The PAN/silica nanofibers were characterized by SEM, TEM, ATR-FTIR and DSC. SEM and TEM images show that beads are formed and silica nanoparticles start to aggregate when the silica content is higher than 2 wt.% in nanofibers. ATR-FTIR spectra and DSC results indicate that there may exist interactions between silica nanoparticles and PAN. The addition of silica nanoparticles also changes the thermal properties of PAN/silica nanofibers. Published by Elsevier B.V.