Objective To systematically explore the key techniques and clinical outcomes of constructing the spatial system for endoscopic thyroidectomy by gasless unilateral axillary approach (GUA), optimize the surgical procedure, shorten the learning curve, and reduce the risk of surgical complications. Methods A retrospective analysis was conducted on 36 patients who underwent gasless endoscopic thyroid surgery via the axillary approach at Hengshui Fourth People’s Hospital between August 2018 and January 2023. Detailed records of clinical data, operative time, complications, and cosmetic outcomes were maintained. The study summarized effective methods for identifying the sternocleidomastoid muscle space and innovatively proposed the “5-8 o’clock positioning technique” for precise localization of the recurrent laryngeal nerve. Results All 36 surgeries were successfully completed without conversion to open surgery. The operative time ranged from 60 to 235 minutes, with an average of 159.4 minutes. The average blood loss was 17.2 mL, and the postoperative hospital stay was 5-7 days. Pathological results revealed: 15 cases of unilateral papillary thyroid carcinoma, 10 cases of thyroid adenoma with hemorrhagic cystic degeneration, and 11 cases of nodular goiter with adenomatous hyperplasia. The complication rate was 13.9% (1 case of transient recurrent laryngeal nerve injury, 2 cases of hoarseness, and 2 cases of subcutaneous effusion). The cosmetic satisfaction rate was 100%. Follow-up of 15 papillary thyroid carcinoma patients for 6-12 months showed no recurrence or metastasis. Conclusions This study investigated the construction of the spatial system in 36 cases of gasless transaxillary approach thyroid surgery. The use of the “5-8 o’clock positioning technique” significantly improved the identification and protection efficiency of the recurrent laryngeal nerve, reducing the risk of nerve injury. The optimization of the surgical procedure, reduction in complication rates, and shortening of the learning curve provide a standardized technical framework that can be widely applied to complex endoscopic surgeries.