Abstract: Objective To investigate the effects of supplemented Gegen Decoction on vertigo symptoms and hemorheology in patients with cervical spondylotic vertebral arteriopathy(CSA). Methods A total of 76 patients with CSA were selected and divided into control group and combined group according to the lottery method, with 38 patients in each group. The control group was treated with flunarizine hydrochloride capsule, and the combined group was treated with supplemented Gegen Decoctionon the basis of the control group. The improvement of clinical symptom, hemorheology indexes and vertebral basilar artery parameters were compared between the two groups. Results The effective rate of the combination group was 92.11%, which was significantly higher than 73.68% of the control group(P<0.05). After treatment, there were significant differences in whole blood viscosity, plasma viscosity, fibrinogen level, resistance index, vertebral basilar artery diameter, systolic blood flow velocity, and diastolic blood flow velocity between the two groups compared with those before treatment(P<0.05), the total blood viscosity, plasma viscosity, fibrinogen level and resistance index of the combined group were significantly lower than those of the control group, the vertebral basilar artery diameter was significantly greater than that of the control group, and the systolic and diastolic blood flow velocity were higher than those of the control group(P<0.05). Conclusion Supplemented - Gegen Decoction for patients with CSA can enlarge the inner diameter of vertebral basilar artery vessels, reduce blood viscosity and circulation resistance, accelerate speed of blood flow, and relieve symptom of vertigo.