The influences of Na and K content on the crystal phase, the microstructure and the electrical property of BaTiO3-based thermistors was found to show typical PTC effects. The crystal phase of powder calcined at 1000oC for 4hrs showed a single phase with BaTiO3, and the crystal structure was transformed from tetragonal to cubic phase according to added amounts of Na and K. In XRD results at 43o~47o, the (Ba0.858Na0.071K0.071)(Ti0.9985Nb0.0015)O3.δ showed (002) and (200) peaks but the (Ba0.762Na0.119K0.119)(Ti0.9975Nb0.0025)O3.δ showed (002), (020) and (200) peaks. In sintered bodies, those calcined at 600oC rather than at 1000oC were dense, and for certain amounts of Na and K showed rapid decreases in grain size. In relative permittivity, the curie temperature due to the transformation of ferroelectric phase rose with added Na and K but decreased in terms of relative permittivity. In the result of the R-T curve, the sintered bodies have curie temperatures of about 140oC and the resistivity of sintered bodies have scores of Ω·cm; the jump order of sintered bodies was shown to be more than 104 in powder calcined at 1000oC.