Objective：To investigate the expression level of nitric oxide synthases（NOS） and nerve growth factor（NGF） in pterygopalatine ganglion of the allergic rhinitis rats. Methods： The expression level of NOS and NGF was detected in pterygopalatine ganglion of the allergic rhinitis rats using histochemical and immunofluorescence staining methods respectively. Results：The number of labelled NOS-positive neurons and NGF-positive neurons was respectively increased significantly（P < 0.01） in pterygopalatine ganglion of the allergic rhinitis rats. Conclusion：NOS and NGF were probably involved in the pathologic mechanisms of the allergic rhinitis by the nerve regulation.