A highly sensitive mixed potential type gas sensor based on stabilized zirconia (YSZ) and CdMoO₄sensing electrode (SE) was developed and used for detection of acetone at 625℃. By comparing the sensing performance for different devices fabricated, the sensor utilizing CdMoO₄-SE exhibited the highest response value (-133.5 mV) to 100 ppm acetone at 625℃, and even could achieve low detection limit of 500 ppb at 625 ℃. The sensor attached with CdMoO₄-SE displayed high sensitivity of -84 mV/decade to acetone in the range of 5-300 ppm at 625℃. The present device also showed good repeatability, selectivity to certain deleterious gases, moisture resistance and acceptable drifts in 10 days measured period at 625 ℃, demonstrating great potential for practical application in acetone sensing detection. Additionally, the sensor involving mixed potential mechanism was proposed and further clarified by polarization curve.