Objective To investigate the clinical value of electrophysiological monitoring of abnormal muscle response (AMR) and brainstem auditory evoked potential (BAEP) in microvascular decompression (MVD) for hemifacial spasm (HFS) via keyhole approach.Methods A total of 158 patients with HFS were enrolled as the monitoring group. They underwent MVD with electrophysiological monitoring of AMR and BAEP. Another 48 patients with HFS were enrolled as the control group. They underwent MVD without electrophysiological monitoring. The outcome and the incidence of postoperative complications were compared between the two groups.Results The monitoring group had significantly higher short-term and long-term response rates than the control group (90.51%[143/158] vs 79.17%[38/48], P<0.05; 95.57%[151/158] vs 87.50%[42/48], P<0.05). In addition, the monitoring group had a significantly lower incidence of postoperative complications than the control group (8.87%[14/158] vs 25.0%[12/48], P<0.05).Conclusions MVD via keyhole approach is an effective method for the treatment of HFS. Neuro-electrophysiological monitoring in the MVD can help to identify the responsible blood vessels, reduce postoperative complications, and improve the surgical effect.