Objective: To investigate the efficacy of functional training of facial mimic muscles for patients with incomplete peripheral facial nerve injury. Methods: Ninety-two patients with 241 injured branches of incomplete peripheral facial nerve injury were divided into a treatment group and a control group. The treatment group consisted of 58 cases that received functional training of facial mimic muscles. The rest of the cases served as controls. Assessment parameters included the House-Brackmann grading system, a quantitative facial nerve function estimating system and electroneurography. According to the three assessments, the facial nerve injury was divided into four grades: normal, minor, moderate and severe. The treatment group started training facial mimic muscle activity 2 weeks after facial nerve injury. After follow-ups of 1 to 4 years, the outcomes were statistically analysed. Results: In the minor facial nerve injury group, there was no significant difference in the time needed for initial recovery (Ti, the time needed for significant recovery of the facial nerve function after injury) and final recovery (Tf, the time point after which no further improvement of facial nerve function was obtained) between the two groups (P > 0.05). No adverse effect was found in these cases. In the moderate facial nerve injury group, the Ti and Tf of the treatment group were shorter than those of the control group (P 0.05). One case had synkinesis. In the patients with severe facial nerve injury, the recovery rate of facial nerve function in the treatment group was higher than that of the control group and the sequelae were less. Conclusion: Functional training of facial mimic muscles cannot shorten the time of recovery for the patients with minor facial nerve injury but it can speed up the recovery and reduce the undesirable sequelae such as synkinesis and hemifacial spasm for the patients with moderate and severe facial nerve injury. Keywords: facial mimic muscle, functional training, facial nerve injury