ObjectiveTo analyze a new classification of the left apicoposterior segmental bronchus and summarize its clinical significance. Methods We accessed the computed tomography imaging data of the inpatients treated in the Department of Thoracic Surgery, Henan Provincial People's Hospital between January and November 2021. We observed and classified the branching pattern of the left apicoposterior segmental bronchus (B1+2) using three-dimensional computed tomography bronchography and angiography (3D-CTBA) technique. And we filtered out the patients who underwent thoracoscopic left apicoposterior segmentectomy and analyzed their clinical data retrospectively to summarize the instructing significance of different bronchial classification in the accurate and safe operation of left apicoposterior segmentectomy. Results Finally 240 patients were collected, including 131 males and 109 females with a median age of 51.0 (19.0-77.0) years. The anatomical pattern of the left apicoposterior segmental bronchus was divided into four main types based on the branching pattern of the outer subsegmental bronchi (B1+2c): type Ⅰ 10% (24 patients), type Ⅱ 54% (130 patients) , type Ⅲ 17% (40 patients) , type Ⅳ 18% (43 patients) and other variations 1% (3 patients). Thirty-two patients smoothly underwent thoracoscopic left apicoposterior segmentectomy, including 23 patients of type Ⅰ and type Ⅱ receiving LS1+2 resection, the other 9 patients of type Ⅲ and type Ⅳ receiving LS1+2 resection (3 patients), LS1+2c resection (4 patients) and LS1+2(a+b) resection (2 patients). Conclusion This new classification systematically and concisely elucidates the branching characteristics of the left apicoposterior bronchus. Different branching types are instructive to the left apicoposterior segmentectomy.