A left-sided thin pneumothorax with about 10% compression of the lung tissue is relatively uncomplicated and can be recovered after aggressive causative and symptomatic treatment. The pleural cavity is a chamber presenting negative pressure, and the lung tissue is adsorbed to the inner wall of the chest cavity, with corresponding contraction and diastole of the lung tissue during inhalation and exhalation. When the pleura or lung tissue ruptures for various reasons, gas will spill out into the chest cavity, forming a pneumothorax and breaking the negative pressure and compressing the lung tissue. The appearance of left lamina propria pneumothorax, need to clarify the cause of the disease, common such as traumatic pneumothorax, alveolar rupture, etc., lung tissue compression of 10%, if the symptoms of chest tightness, chest pain, dyspnea and other symptoms are not obvious, you can choose a conservative treatment, pneumothorax can be absorbed on its own. If the symptoms are obvious, if necessary, closed chest drainage treatment is feasible, can also be cured, and is not serious. After the appearance of pneumothorax, it is recommended to seek medical treatment in time, to clarify the cause of the diagnosis, under the guidance of professional doctors, active treatment.