In this study, the polyvinyl alcohol (PVA)/carbon nanotubes (CNTs) conductive hydrogel film is successfully prepared by the one-pot method. The PVA/CNTs composite film presents a uniform three-dimensional mesh structure. The CNTs are uniformly dispersed in the hydrogel matrix to form a stable conductive network. The strain sensing performance of PVA/CNTs conductive hydrogel is investigated. It shows excellent dynamic response properties and stability with a GF of 6.34 within 0–10% tensile strain. The hysteresis of PVA/CNTs is as low as 0.333% ± 0.220%（mean ± SD）. Further application studies prove that the strain sensor based on PVA/CNTs conductive hydrogel can accurately monitor the motion status of human joints, and can effectively identify motion abnormalities in stroke patients in rehabilitation assistance assessment.