The ternary system NTC (negative temperature coefficient) powders of Co1.5Mn1.5-XNiXO4 (X=0, 0.1, 0.3, 0.5, 0.7, 1.0) materials were prepared via sol-gel method. The particle size of calcined powders, phase structure, infrared absorption spectra and electrical properties were characterized by using laser particle size analyzer, XRD, IR and electrical measurements, respectively. Combined with the results of XRD and IR spectra, the relation between cation distribution and electrical properties of NTC thermistors were investigated, which provided evidence for high precision and reliability of NTC material. The results of electrical measurements indicated that the electrical resistivity display a U-shape curve with the increase of Ni content, whereas the thermal constant B-25/50 decreased remarkably from 4427 to 2429 K. This means that electrical resistivity and B25/50 of Co1.5Mn1.5-XNiXO4 system could be adjusted to the desired values and then considered this ternary system as advanced semi-conducting materials for NTC thermistor applications.