The acetaldehyde vapor produced in industrial production and life needs to be monitored in real time and efficiently, WO3 nanoplates and a series of Ti3C2Tx-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 Ti3C2Tx can enhance the gas sensing performance of WO3 nanoplates. The optimized gas sensing operation temperature is 80 ℃ for 7%(mass fraction) Ti3C2Tx-WO3 composite material. The sensitivity of 7% Ti3C2Tx-WO3 composite material to 100 μL/L acetaldehyde vapor at 80 ℃ is 32.9 within a low detection limit of 0.1 μL/L.