Iatrogenic facial nerve paralysis is one of the major and drastic complications of ear surgery. We report a case of a 20-year-old female patient with simple chronic otitis media who underwent mastoidectomy and tympanoplasty. During the mastoidectomy process the facial nerve was unintentionally destroyed, leaving a gap of 8-10 mm in the third segment of the intratemporal facial nerve. The nerve was repaired with a nerve cable graft obtained from the vicinity. On the 42nd day, autologous mesenchymal stem cell transplantation was performed after facial nerve trauma. The patient's facial nerve paralysis has recovered from House-Brackmann grade VI to IV within a week and then to III in the fifth month. The rapid, postoperative progress, and the early follow-up results are discussed. This case represents the first bone marrow stem cell application in a peripheral nerve, namely the facial nerve.