A series of planar mixed-potential type sensors based on AMn₂O₄(A = Co, Zn and Cd) sensing electrodes, yttria-stabilized zirconia solid electrolyte, and N reference electrode were fabricated for acetone detection. All of the sensing materials AMn₂O₄(A = Co, Zn and Cd) with a spinel structure were synthesized by a simple sol-gel method. The present results showed that the sensor based on CdMn₂O₄-SE (Sensing Electrode) exhibited the highest response of - 38 mV to 10 ppm acetone and a low detection limit of 200 ppb. And the value of the sensing signal to 200 ppb acetone was about -1.3 mV, which ma the requirement of diabetic diagnosis. Furthermore, the sensor exhibited excellent repeatability and high sensitivity of - 28 mV/decade in the range of 1-50 ppm acetone. It also performed acceptable stability, including long-term stability and consistency during the test. The high sensing characteristics of the sensor to acetone mainly depended on the high electrochemical catalytic activity of the sensing material CdMn₂O₄.