This clinical study aims to evaluate the efficacy and safety of spinal cord stimulation combined with non-invasive motor imagery brain-computer interface rehabilitation training in patients with upper limb motor dysfunction after chronic stroke. The study includes an experimental group receiving spinal cord stimulation combined with motor imagery brain-computer interface rehabilitation training and a control group receiving motor imagery brain-computer interface rehabilitation training alone. The primary outcome is upper limb motor function assessed by the Fugl-Meyer Assessment for Upper Extremity. Secondary outcomes include muscle tone, upper limb functional activity, activities of daily living, adverse events, serious adverse events, and exploratory neurophysiological and neuroimaging indicators.