Flexible sensors require good tensile properties, flexibility, and sufficient sensitivity to monitor and transmit small strain changes in motion. MXene/PVA composite hydrogel was synthesized by polyvinyl alcohol (PVA) and MXene. Scanning electron microscopy showed that MXene was uniformly dispersed in the composite hydrogel. Fourier transform infrared spectroscopy verified the strong hydrogen bonding interactions between MXene and the polymer. The prepared MXene/PVA composite hydrogels exhibited a finite tensile strain of 796% and an energy of rupture of up to 48.66 kJ/m³, suggesting excellent mechanical properties. The electrical resistance change rate of the MXene/PVA composite hydrogels showed a good linear response to the tensile strain (400%~800%), with a response time of 0.3 s. These advantages make it possible to monitor random movements of the human body in real time, such as swallowing the throat, bending the fingers, flexing and extending the knees.