Objective To study the immunoreactivity of Calcitonin gene-related peptide (CGRP) in the facial nerve when Hemifacial Spasm is occurring. Methods The electrophysiological technique was used to explore abnormal muscle response (AMR) which was characteristic of Hemifacial Spasm.The animal models of Hemifacial Spasm in New Zealand white rabbits were established by compressing the main trunk of artificial demyelinated facial nerve with the temporal superficial artery. At 6 weeks after surgery, the facial nerves were taken from the experimental group and control one, the immunohistochemistry for CGRP using polyclonal antibody with ABC kit was performed in the facial nerves; at the same time, the observation for the facial nerves of light and transmission electron microscope was performed. Results The facial nerve demyelinated and the axons retrogressively changed, CGRP immunoreactive positive fibers were significantly detected in experimental groups; whereas this phenomenon was not found in control group. Conclusion CGRP can nutrien the injured facial nerve and plays an important role in the pathogenesis of Hemifacial Spasm. Objective To study the immunoreactivity of Calcitonin gene-related peptide (CGRP) in the facial nerve when Hemifacial Spasm is occurring. Methods The electrophysiological technique was used to explore abnormal muscle response (AMR) which was characteristic of Hemifacial Spasm. The animal models of Hemifacial Spasm in New Zealand white rabbits were established by compressing the main trunk of artificial demyelinated facial nerve with the temporal superficial artery. At 6 weeks after surgery, the facial nerves were taken from the experimental group and control one, the immunohistochemistry for CGRP using polyclonal antibody at ABC of the facial nerves of light and transmission electron microscope was performed. groups; yet this phenomenon was not found in control group. Conclusion CGRP can nutrien the injured facial nerve and plays an important role in the pathogenesis of Hemifacial Spasm.