A novel one-pot synthesis method for Pt-loaded SnO2 nanofibers is reported on the basis of the sol-gel and electrospinning-combined process. The ultraviolet illumination was used for in-situ growth of Pt nanoparticles in the electrospinning solution. The sensing capability of pure SnO2 nanofibers was significantly improved by loading Pt nanoparticles. The Pt-loaded SnO2 nanofibers showed a good selectivity to toluene gas. The optimization of Pt amount in SnO2 nanofibers was essential to obtain best sensing performances. The one-pot synthesis method developed in this work may extend the use of oxide nanofibers in chemical gas sensors.