Pt-functionalized NiO composite nanotubes were synthesized by a simple electrospinning method, and their morphology, chemistry, and crystal structure have been characterized at the nanoscale. It was found that the Pt nanoparticles were dispersed uniformly in the NiO nanotubes, and the Pt-functionalized NiO composite nanotubes appeared some dendritic structure in the body of nanotubes just like a thorns growing in the nanotubes. Compared with the pristine NiO nanotubes gas sensor and other NiO-based gas sensor reported previously, the Pt-functionalized NiO composite nanotubes based gas sensor showed substantially enhanced electrical responses to target gas (methane, hydrogen, acetone, and ethanol), especially ethanol. The NiO-Pt 0.7% composite nanotubes based gas sensor displayed a response value of 20.85 at 100 ppm at ethanol and 200 °C, whereas the pristine NiO nanotubes based gas sensor only showed a response of 2.06 in the same condition. Moreover, the Pt-functionalized NiO composite nanotubes based gas sensor appeared outstanding gas selectivity for ethanol against methane, hydrogen, and acetone. The reason which the Pt-functionalized NiO composite nanotubes based gas sensor obviously enhanced the gas sensing performance is attributed to the role of Pt on the chemical sensitization (catalytic oxidation) of target gases and the electronic sensitization (Fermi-level shifting).