Given the considerable harm that NO2 poses to the environment and human health, developing reliable NO2 detection sensors is crucial. Herein, a flexible, multifunctional sensor was successfully synthesized through hydrothermal and the wet impregnation methods using an elastic PU yarn as the substrate. This sensor, named Au/VTe2/Ti3C2Tx–PU, was characterized via X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy to analyze its structure, chemical valence states, and micromorphology. At room temperature (23 °C), the sensor demonstrated an exceptionally high response to NO2 gas, with a response value of 1.72 at 50 ppm as well as low response and recovery time of 33 and 38 s. Additionally, testing of the strain performance of Au/VTe2/Ti3C2Tx–PU showed that this flexible sensor exhibits high strain sensitivity, excellent repeatability, and durability, making it suitable for detecting subtle human movements. Overall, the synthesized sensor is in considerable advantages in terms of both gas-sensing performance and tensile performance, exhibiting broad application prospects in human motion and health monitoring.