Objective To evaluate the effectiveness and safety of episodic migraine prevention with the percutaneous mastoid electrical stimulator (PMES). Methods This was a randomized, double-blind, and sham-controlled trial that involved four medical centers. Episodic patients with at least two migraine attacks every month were randomly 1:1 to PMES or sham stimulation treatment. The treatments were performed daily for 45 minutes over 3 months. The primary outcomes were change in migraine days per month and the 50% response rate. Results The PMES group had a significantly greater reduction of migraine days in the third month than the sham group (-71.3% vs. -14.4%, p < 0.001). The 50% response rate of migraine days in the PMES group (≥50% reduction of migraine days compared with the baseline) was significantly higher than that in the sham group (82.5% vs. 17.5%, p < 0.001). In the PMES group, 60% of the patients had a ≥75% reduction of migraine days in the third month, and 35% of the patients had no migraine attack in the third month. No patients in the sham group had a ≥75% reduction of migraine days. There were no adverse events in either group. Conclusion Treatment of migraine using non-invasive PMES was safe and effective.