In this study, Ni0.79(Mn2.21-χCuχ)O4 (x=0~0.25) specimens were prepared by using a conventional mixed oxide method. All specimens were sintered in air at 1,℃ for 12 h and cooled at a rate of 2℃/min to 800℃, subsequently quenching to room temperature. We investigated the structural and electrical properties of Ni 0.79(Mn2,21-χCuχ)O4 specimens with variation of CuO amount for the application of NTC thermistors. As results of X-ray diffraction patterns, all specimens showed the formation of a complete solid solution with cubic spinel phase. The relationship between ln ρ and the reciprocal of absolute temperature(1/T) for the NTC thermistors was shown linearity, which exhibited the typical NTC thermistor properties. With increasing the amount of CuO, resistivity at room temperature, B-value, and temperature coefficient resistance decreased.