The severity of pneumothorax relies on a chest x-ray that shows the degree of lung atrophy and the amount of air that has accumulated in the chest cavity. In the case of spontaneous or closed pneumothorax, the degree of lung atrophy will not reach 100% because the intrathoracic pressure is still lower than the atmospheric pressure, and the degree of lung atrophy will not be 100%, but will be roughly determined by the patient’s signs, such as dyspnea, chest pain, fullness of the chest on the affected side, clear breath sounds, and shifting of the trachea. For example, if the patient is still able to breathe, but only develops pain in the chest, the degree of collapse of the chest may have already been more than 30%. If the patient has developed dyspnea, accompanied by the sounding of the voice that appears to be painful, and there is a displacement of the trachea to the healthy side, it means that the degree of atrophy is more than 50%. If it is an open pneumothorax, the outside air has entered the chest cavity, the pressure is greater than the pressure inside the chest cavity, the lung is basically 100% atrophied, and the patient has already lost the respiratory function, so urgent treatment is needed. This kind of are estimated, there is a pneumothorax after the judgment through the physical signs, for closed pneumothorax, should be timely for the puncture of the pleural cavity, do thoracic drainage to exclude the accumulation of air, so that the lungs as early as possible to expand.