This study evaluated the therapeutic efficacy of high-frequency repetitive Peripheral Magnetic Stimulation (rPMS) in treating acute idiopathic facial nerve palsy (IFP) and the role of neuromuscular ultrasonography. Forty patients with unilateral acute IFP were divided into intervention and control groups. Both groups received medical treatment, routine rehabilitation, and ultrasonography assessments. The intervention group underwent 10 sessions of high-frequency rPMS. After six weeks, the intervention group showed significant improvements in House-Brackmann grading and Facial Disability Index scores, and a significant decrease in the facial nerve diameter at the proximal portion without sheath compared to the control group. High-frequency rPMS appears to be an effective adjunctive treatment for acute IFP.