Post-stroke spasticity, a common sequelae of upper motor neuron lesions, results in motor control deficits and pathological hypertonia that not only reduce patients’ activities of daily living but may also cause impairment of adaptive neuroplasticity. Repetitive peripheral magnetic stimulation (rPMS), as a novel non-invasive neuromodulation technique, demonstrates unique clinical potential through targeted modulation of electromagnetic coupling effects in the peripheral neuromuscular system. Although current international studies have validated the therapeutic potential of rPMS for spasticity, significant heterogeneity persists in elucidating its mechanisms of action, optimizing parameter protocols, and standardizing outcome assessment systems. This review innovatively synthesized recent randomized controlled trials (RCTs) and mechanistic evidence, systematically summarizing rPMS-mediated multidimensional intervention paradigms for upper- and lower-limb spasticity. It rigorously examined the correlations between stimulation frequency parameters (low-frequency vs. high-frequency), anatomical targeting (nerve trunk vs. motor point), and clinical outcomes including spasticity severity, motor function, and quality of life. Crucially, the analysis reveals that rPMS may ameliorate spasticity after stroke through dual mechanisms involving local neuroelectrophysiological modulation and central sensorimotor network reorganization, thereby providing a theoretical foundation for developing individualized rPMS clinical protocols and establishing precision treatment strategies.