A SO3H-bearing nanofiber mat was synthesized and investigated as a novel heterogeneous acid catalyst. Preoxidated polyacrylonitrile nanofiber mat was prepared via electrospinning and heat treatment, and then reacted with chlorosulfuric acid to introduce the sulfonic groups. The nanofiber mat owned high acidity of 2.99 mmol/g. The preoxidation and sulfonation were examined by FT-IR spectroscopy. elemental analysis and X-ray diffraction spectroscopy (XRD). The fiber morphologies were characterized by scanning electron microscopy (SEM). The catalytic activities and reuse of the prepared nanofiber mat solid acid catalyst have been evaluated for the acetalization and esterification. The regular fiber mat structure could significantly facilitate the recovery and reuse of the catalyst. The excellent catalytic performance and easy recycling made the novel fiber mat solid acid hold great potential for the green chemical processes. (C) 2012 Elsevier B.V. All rights reserved.