Nickel doped tin dioxide nanoparticles (NPs) have been synthesized by precipitation method. Polysulfone (PSU)/NPs nanocomposites were prepared by electrospinning procedure using two precursor solutions. The resultant nanostructures were investigated by X-ray diffraction, electron scanning microscopy (SEM), transmission electron microscopy (TEM) and energy -dispersive Xray spectroscopy (EDX), which confirmed well oriented nanofibers and good dispersion of NPs over them. The nanocomposites exhibit a strong UV emission band positioned at about 374 nm (lambda(ex)= 320 nm) and the blue and green emissions are suppressed. The time-resolved photoluminescence studies have been performed and the lifetimes were evaluated. The fluorescence decay reveals a biexponential behavior. A higher thermal stability was observed after incorporation of nanoparticles in nanofiber composites. Gas response properties (methanol, ethanol, ammonia, formaldehyde and butane) at different temperatures from 50 to 180 degrees C were discussed. Gas sensing experiments suggest that PSU/Ni doped tin oxide nanocomposites showed highly enhanced sensing performances to methanol and ammonia as compared to pure PSU/tin oxide nanofiber. The PSU/NPs nanocomposites could be used for methanol and ammonia detection at room temperature.