Objective To compare the distribution characteristics of the main thoracic curve Cobb angle in Lenke type 1 adolescent idiopathic scoliosis (AIS) patients, and differences in flexibility, correction rate, and correction index measured by different segmental suspension traction methods. Methods Totally 48 Lenke type 1 AIS patients, who underwent one-stage posterior 3-dimensional spinal deformity correction with bone graft fusion and internal fixation in The First Affiliated Hospital of Naval Medical University (Second Military Medical University) from Jan. 2015 to Dec. 2018, were enrolled. The main thoracic curve was divided into proximal (T₅-T₇ or T₆-T₈), middle (T₇-T₉ or T₈-T₁₀), and distal (T₉-T₁₁ or T₁₀-T₁₂) segments, and Cobb angles were measured for each segment. Flexibility, correction rate, and correction index (correction rate/preoperative flexibility) were calculated for different segments. Statistical analysis was performed using the analysis of variance of randomized block for comparison. Results The preoperative average age was (14.31±2.24) years, the total Cobb angle was (51.25±11.86)°, and the average Risser grade was 2.88±1.93. The average follow-up time was (38.75±8.82) months. The preoperative Cobb angle of the proximal segment was similar to that of the distal segment (［13.31±5.10］ ° vs ［13.94±5.67］ °, P＝0.757), and the Cobb angle of the middle segment (24.00±5.61)° was greater than that of the proximal and distal segments (both P＜0.001). The proportions of the proximal, middle and distal Cobb angle to the total Cobb angle were (25.72±7.97)%, (47.08±5.22)% and (27.20±8.00)%, respectively. Preoperative lateral flexion flexibility of the distal segment was significantly higher than that of the proximal and middle segments (［64.01±24.18］% vs ［35.00±18.02］%, ［41.49±17.65］%, both P＜0.001). The correction rates at 1 week postoperatively were as follows: proximal segment (74.61±15.80)%, middle segment (65.66±16.36)%, and distal segment (73.76±19.41)%, with no significant difference (P＝0.280). The correction indexes were as follows: proximal segment 2.41±1.20, middle segment 2.03±1.45, and distal segment 1.49±1.31, and the correction index of the proximal segment was significantly higher than that of the distal segment (P＝0.040). At the last follow-up, the correction rates were: proximal segment (71.10±14.07)%, middle segment (62.39±13.47)%, and distal segment (69.75±17.53)%, with no significant difference (P＝0.226). The correction indexes were as follows: proximal segment 2.24±1.10, middle segment 1.92±1.30, and distal segment 1.39±1.10, and the correction index of the proximal segment was significantly higher than that of the distal segment (P＝0.026). Conclusion In Lenke type 1 AIS patients, the proximal, middle, and distal segments account for 25.72%, 47.08%, and 27.20% of the main thoracic curve Cobb angle, respectively. The suspension traction method has the strongest ability to evaluate the flexibility of the distal segment, that is, the distal segment is most flexible under the suspension position, and the postoperative correction rate of each segment is similar.