The invention is applied to the field of medical image segmentation technology, and provides a bronchial partition method and a system thereof. The bronchial partition method includes the following steps: a first segmenting step, segmenting and extracting a main area of the lung and the bronchus from an original lung image through three-dimensional growth algorithm; a bronchus enhancing step, carrying out multiple times of expansion operations and multiple times of corrosion operations to the main area of the lung and the bronchus; and a second segmenting step, extracting the bronchus from the main area of the lung and the bronchus after the multiple times of expansion operations and multiple times of corrosion operations. The bronchial partition method strengthens the bronchus through information of vascular so as to avoid effect of gray value change, and a segmenting result of the bronchus is enabled to be more stable and accurate.