Objective To establish a rat model of spinal root avulsion and to validate the model by brain-derived neurotrophic factor (BDNF) treatment. Methods To evaluate the motor neuron loss, 5 male SD rats were used to undergo spinal root avulsion surgery. One week later, the number of motor neurons in the ventral horn of the spinal cord was assessed by histopathology using immunohistochemical staining with a choline acetyl transferase (ChAT) antibody. After this pilot study, 40 male SD rats at 7 weeks of age were randomly divided into 4 groups: two control groups, BDNF preventive and treatment groups. Results All rats recovered well post-surgery and no obvious abnormality was observed. Compared with the contralateral side, the number of motor neurons in the ipsilateral avulsed side was significantly decreased at one week after surgery (20.06%, P <0.05). Compared with the control group, there was a significant increase in ChAT positive neurons in the BDNF preventive group (17.85% vs. 93.06%, P < 0.0001) or BDNF treatment group (1week after surgery) (26.94% vs. 86.87%, P < 0.0001), indicating that the motor neurons were effectively protected by BDNF. Conclusions A rat model of spinal root avulsion is successfully established, which can be valuable for studies of amyotrophic lateral sclerosis and drug discovery efforts.