With large surface area, metal oxide porous nanostructures usually exhibited enhanced sensitivities when used as chemical sensors. In this work, porous SnO2 nanowires (PNWs) with the diameter of about 130 nm and length up to 10 mu m are synthesized by a controlled two-step method including electrospinning followed with hydrothermal etching treatment by Na2S solution, which were used to fabricate high-performance gas sensors. Studies found that, compared with the electrospun pristine SnO2 NWs without hydrothermal treatment, the SnO2 PNWs exhibited remarkably enhanced gas sensing performances, including two times higher responsivity to ethanol. The method used here may be easily extended to synthesize other metal oxide nanostructures for high performance chemical sensors. (C) 2017 Elsevier B.V. All rights reserved.