The acetaldehyde vapor produced in industrial production and life needs to be monitored in real time and efficiently, WO₃ nanoplates and a series of Ti₃C₂T_x-WO₃ composite materials were synthesized by a hydrothermal method. The structure and morphology of the as-prepared materials were investigated by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The gas sensing properties of materials were analyzed. The results show that the addition of Ti₃C₂T_x can enhance the gas sensing performance of WO₃ nanoplates. The optimized gas sensing operation temperature is 80 ℃ for 7%(mass fraction) Ti₃C₂T_x-WO₃ composite material. The sensitivity of 7% Ti₃C₂T_x-WO₃ composite material to 100 μL/L acetaldehyde vapor at 80 ℃ is 32.9 within a low detection limit of 0.1 μL/L.