Here we demonstrate the preparation and improved hydrogen monitoring properties based on p-NiO/n-SnO2 heterojunction composite nanofibers via the electrospinning technique and calcination procedure. NiO/SnO2 heterojuction composite nanofibers were spin-coated on the ceramic tube with a pair of Au electrodes for the detection of hydrogen. Extremely fast response recovery behavior (similar to 3s) has been obtained at the operable temperature of 320 degrees C, based on our gas sensor, with the detection limit of approximate 5 ppm H-2. The role of the addition of NiO into the SnO2 nanofibers and the sensing mechanism has also been discussed in this work.