Ce_0.8Gd_0.2O_1.95-based mixed potential type acetone sensors attached with La₂CoMnO₆and La₂CuMnO₆were fabricated. Sensing performance of these two sensors were measured, and related results showed that La₂CuMnO₆was more sensitive to acetone compared with La₂CoMnO₆. The sensor using La₂CuMnO₆as sensing material has state and distinctive response in the range of 10–1000 ppm acetone, and the response value of the sensor changed linearly with the logarithm of acetone concentration with the slope of −49.3 mV/decade. The typical 90% response and recover times of the sensor to 50 ppm were both 13 s, and to 500 ppm were 3 s and 13 s. Besides, the sensor also displayed excellent repeatability, good humidity stability and long-term stability. The better sensing performance of the sensor attached with La₂CuMnO₆was explained thorough the electro catalytic activity validated by polarization curves and morphology validated by SEM.