The composite electroceramics Ba Sn,Sb.O3qBi2O3 were designed and fabricated. With the increasing content of Bi2O3, the resistivity and the radius shrinkage of this composite disk rapidly increased. The structure of this composite was investigated by XRD, EPA and SEM. The conductivity of this ceramic has been measured as a function of temperature. The experimental results proved that this composite ceramic is one kind of thermistor with linear negative temperature coefficient in the temperature range 0–2508C. And the resistivity at room temperature can be adjusted by monitoring the content of Bi2O3. The typical temperature coefficient of resistor was around 2.3=10y3r8C. q2000 Elsevier Science S.A. All rights reserved.