Objective: To observe the influences of ligation or non-ligation of the five main tributaries of the great saphenous vein (GSV) on the efficacy of endovenous microwave ablation for GSV varicose veins. Methods: Endovenous microwave ablation was performed in 600 patients with GSV varicose veins. Of the patients, 400 cases (635 limbs) underwent GSV high ligation plus endovenous microwave ablation of the main GSV trunk, and percutaneous microwave ablation of the superficial varicose veins and pathological perforating veins of the legs (observational group), while another 200 cases (313 limbs) were subjected to ligation of the five main GSV tributaries in addition to the above mentioned procedures (control group). Results: Satisfactory clinical efficacy was obtained in both groups of patients after operation. No significant differences were noted between the two groups in the improvement of the superficial varicose veins, leg swelling, pigmentation and ulcers, as well as the incidence of postoperative complications and 5-year recurrence rate (all P>0.05). Ultrasound imaging showed that the flow velocity and inner diameter of the common femoral vein in observational group were significantly reduced after operation versus those before operation (both P<0.05); while in control group, the flow velocity of the common femoral vein was significantly decreased (P<0.05), but the decreased level of the inner diameter did not reach a statistical significance compared with that before operation (P>0.05). Conclusion: Whether the five main GSV tributaries are ligated or not does not substantially influence the outcomes of endovenous microwave ablation in treatment of GSV varicose veins.