A facile electrospinning technique followed with calcinations in air has been accepted as a straight forward protocol for the research and development of SnO2/TiO2 heterostructures which are composed of SnO2 nanoparticles and TiO2 nanofibers. Characterizations of the nanocomposites by series of testing techniques indicate that the SnO2 nanoparticles were prepared and uniformly anchored on the surface of TiO2 nanofibers. Gas sensors were fabricated to investigate the gas-sensing behaviors of SnO2/TiO2 nanocomposites. Comparing with pure SnO2 nanoparticles and TiO2 nanofibers, SnO2/TiO2 nanocomposites exhibited better gas-sensing performance. The SnO2/TiO2 heterojunctional composites with the mass ratio of 1.5:1 presented an optimum operating temperature of 240 degrees C. The maximum gas response relative to 100 ppm ethanol is 9.58, which is about 1.89 and 1.88 times higher, respectively, than pure TiO2 nanofibers and SnO2 nanoparticles. Meanwhile, the gas sensors prepared with SnO2/TiO2 nanocomposites also had shorter response and recovery time and long term stability. The enhanced sensing properties could be ascribed to the formation of heterojunction and the synergetic effect of SnO2 and TiO2 together with its unique nanoparticle attached fibrous architectures.