CdFe2O4 powder with the structure of spinel-type was fabricated by sol-gel method in the citric acid system. The structure and the crystal phase of the powder were characterized on an X-ray diffractometer (XRD). The shape and the size were analyzed by transmission electron microscope (TEM). Several items were investigated, including effects of calcining temperature on gas-sensing properties, gas response vs. working temperature, selectivity and long-term stability. The results demonstrated that the CdFe2O4 sensor prepared with the powder calcined at 700 degrees C has a high response, an excellent selectivity, a quick response behavior, and a good stability to ethanol comparing with the CdFe2O4 sensors which dealt with at other temperatures. Its response to 100ppm ethanol is 55 working at 250 degrees C. (c) 2007 Published by Elsevier B.V.