A series of spinel oxides Co1-xZnxFe₂O₄(x = 0, 0.3, 0.5, 0.7 and 1) prepared by a facile sol-gel method were used as sensing electrodes of mixed potential type yttria stabilized-zirconia (YSZ)-based gas sensor for detection of acetone. The present study mainly focused on the influence of different proportions of cobalt and zinc in Co1-xZnxFe₂O₄-sensing electrode (SE) on the acetone sensing properties for the sensor, and the results showed that when x = 0.5, the fabricated sensor exhibited a largest sensitivity of -63 mV/decade to 5-100 ppm acetone at 650℃. The response signal of the present sensor to 50 ppm acetone was as large as -112 mV, and even could achieve low detection limit of 300 ppb at 650 ℃, which had a faithful response at this concentration. In addition, the present device also displayed good reliability, good cross sensitivities in the presence of various interfering gases, slight sensitive effect to humidity and good stability over 40 days at 650 ℃. Moreover, the polarization curve was measured to further demonstrate the mixed potential mechanism.