| Objective To investigate the clinical efficacy and influencing factors of microwave ablation(MWA) for benign thyroid nodules. Methods A retrospective analysis was performed on 68 patients with benign thyroid nodules who underwent MWA in the Department of Endocrinology, Fuyang People's Hospital Affiliated to Anhui Medical University from January 2020 to June 2021, and were followed up for 12months after operation. The size changes of nodules and the adverse reactions of surgery were observed at 1 month, 3 months, 6 months and 12months after operation. Results A total of 101 benign thyroid nodules in 68 patients were treated with MWA, and the effective rate was 94.06%. The longest diameter, volume and volume reduction rate(VRR) of thyroid nodules before ablation, 1 month, 3 months, 6 months, and 12 months after surgery were reduced, there were statistically significant differences in the rate(P<0.05). The results of linear regression analysis showed that the influencing factor of the VRR of thyroid nodules at 12 months after MWA was the longest diameter(β=-3.734, 95% CI:-7.340~-0.127, P=0.043). In 12 months after MWA serious adverse reactions included hoarseness in 2 cases(2.94%) and hypothyroidism in 1 case(1.47%). Conclusion MWA is one of the effective treatment methods for benign thyroid nodules, and the longest diameter of nodules may be an influencing factor for the VRR of benign thyroid nodules.