Here, the porous SnO₂/Zn₂SnO₄sensing electrode material prepared by facile hydrothermal method was applied to fabricate the mixed-potential-type gas sensor based on yttrium-stabilized zirconia (8 mol% Y₂O₃-doped ZrO₂) solid electrolyte plane substrate for effectively detecting acetylene (C₂H₂) at 700℃. In terms of the sensing characteristics of the C₂H₂gas sensor, the response value toward 100 ppm C₂H₂was -82.3 mV, and the detection limit of C₂H₂was lowered to 500 ppb. The Delta V of the sensing device varied piecewise linearly with the logarithm of C₂H₂concentration gradient range of 0.5-2 and 5-1000 ppm, with sensitivities of -12 and -56 mV/decade, respectively. In addition, the sensor exhibited good humidity stability, long stability, and selectivity to C₂H₂at 700℃. More interestingly, after high-temperature measurement (700℃) for 20 consecutive days, the sensor continued to present good response transients, sensitivity, and reproducibility to C₂H₂. Furthermore, the sensing mechanism of the mixed-potential-type sensor was verified by measuring the polarization curves and complex impedance curves.