Objective To explore the effect of tension-free layer-by-layer suture technique on incision healing in patients undergoing open thyroid surgery. Methods A total of 52 patients who underwent open thyroid surgery in Inner Mongolia People's Hospital from January to December 2024 were selected, and they were divided into group A and group B by the random number table method, with 26 patients in each group. Group A was given traditional tension suture, and group B was given tension-free layer-by-layer suture. The incision healing, surgical indicators, incision-related complication rate, incision scar status and satisfaction were compared between the two groups. Results The incision primary healing rate of group B was 100.00%, which was higher than 84.62% of group A (P <0.05). There were no significant differences in operation time and intraoperative blood loss between the two groups (P >0.05). The incision length of group B was shorter than that of group A (P <0.05). The incidence of incision-related complications in group B was 0, which was lower than 11.54% in group A (P <0.05). The VSS scores of group B at 1, 3 and 6 months after operation were lower than those of group A (P <0.05). The satisfaction score and satisfaction rate of group B were higher than those of group A (P <0.05). Conclusion The application of tension-free layer-by-layer suture technique in patients undergoing open thyroid surgery can effectively promote incision healing, reduce the risk of incision-related complications, improve the appearance of incision scars, and thus help to improve patients' satisfaction with surgical effects, which has definite clinical application value.