Objective: To study responses of injured DRG neurons to sympathetic stimulation with different temporal stimulating pattern. Methods: In chronically compressed DRG model, the spontaneous activity of single fiber from the injured DRG neuron was recorded, lumbar sympathetic trunk was electrical stimulated, and the responses of DRG neurons caused by chaotic and periodic sympathetic stimulation were compared. Results: It was found that the response of DRG increased gradually as the sympathetic stimulating frequency increased from 5 Hz to 20 Hz(P