Abstract: This paper reports experimental results on the oxygen sensing of poly crystalline rutile. Experimental results showed that the parameter m in oxygen partial pressure dependence of electical conductivity for the rutile is related to the temperature. A random point defect model was established in this paper for a general case. The model was used to explain our and other experimental results, and the model aslo predicts that the parameter m is related to the concentration of impurity, and the oxygen partial pressure.