Lung trapping is a condition in which multiple parts of the lung, such as the entire lung, multiple segments of tissue, or lobes of the lung show a decrease in volume or air content, and the site of lung trapping and the area of involvement are shown to be white on x-ray, creating a drop-like pattern. Because of the reduced translucency of the area, the surrounding tissues such as bronchial tubes, pulmonary blood vessels, and interstitial tissues are shifted from the high pressure to the low pressure area, and gather to the area of atelectasis, which suggests the presence of atelectasis or bronchial rupture, and the condition is improved by chest CT or chest MRI examination as soon as possible. If the diagnosis is traumatic bronchial rupture is easy to complicate shock, immediately anti-shock while emergency surgery to repair the lung tissue, if it is a mass caused by pulmonary atelectasis, should be performed as soon as possible fiberoptic microscopy and pathological biopsy examination, to determine the benign and malignant nature of the elective surgical resection of the mass.