Abstract: Objective To observe the treatment effects of botulinum toxin type A on benign bilateral masseter hypertrophy. Methods Forty-six patients in the department of plastic and reconstructive surgery in Chinese PLA General Hospital were enrolled as research subjects from May 2013 to August 2014. Standardized photographs were taken for each patient before the injection and at 3 months, 6 months, 9 months after injection. The changes of facial morphology were observed by the patients themselves, the operator and the third party observation. Results The self-satisfaction achieved in 89.3% patients, the efficiency of treatment effectiveness rate evaluated by operator was 97.8%, and it was 100% by the third party observation. Conclusion Botulinum toxin type A injection is effective and easy-to-use option for masseter hypertrophy, the evaluations from the patients, operator and the third party shows high consistency.