Abstract: Objective To study the repair of brachial plexus nerve defect with chemically extracted acellular nerve allograft. Methods Brachial plexus nerve defect in 23 patients was repaired with chemically extracted acellular nerve allograft from February 2004 to March 2009 in our hospital.Thirty-two 2-9cm long（mean 4.9±2.2cm long） nerves were grafted.The patients were regularly followed up,during which their outcome was assessed by observing their sensation and motion function,EMG and ultrasonic examination findings. Results The patients were followed up for an average time of 33-94 months（mean 71.82±18.50 months）.The excellent and good therapeutic rate for chemically extracted acellular nerve allograft was 69.6% and 68.6% according to the grafted nerves.The effect of chemically extracted acellular nerve allograft was poor on root avulsion and transitional area injury of brachial plexus nerve.The longest allograft length was 7cm（mean 4.6±1.64cm） in 8 patients with an excellent outcome,9cm（mean 6.67±1.61cm） in 8 patients with good outcome,and 8cm（mean 4.5±2.7cm） in 6 patients with a poor outcome（P＜0.05）.Of the 18 patients with blunt injury,13 had a good outcome.Of the 5 patients with sharp injury,3 had a good outcome. Conclusion Chemically extracted acellular nerve allograft can repair brachial plexus nerve defect with a good clinical outcome.The location and severity of injury and the length of nerve allograft affect its prognosis.