The old phlegm after lung surgery can be relieved by knocking back to expel phlegm, oral medication, nebulized inhalation and suction. 1. Knocking on the back to expel phlegm: the correct method is to flex the fingers, the back of the hand, from bottom to top, from both sides to the center, knocking on the back of the back in a strong, rhythmic and even manner, so as to make the phlegm in the lungs and bronchial tubes to be discharged through the vibration of the chest wall. 2. Oral medication: Oral expectorant medication can be used to relieve the symptoms, common medications include Ambroxol, Carboxymethylstilbestrol, etc. If there is a bacterial infection in the lungs, antibiotics can be added to the treatment, such as ceftazidime and levofloxacin. 3. Nebulization inhalation: through the high-speed oxygen airflow, the liquid medication will be nebulized and sent to the trachea and bronchial tubes directly through the respiration, and the effect is more obvious than the oral effect, and the commonly used nebulized medications include budesonide, ambroxol and so on. 4. Suction: it is through the suction machine, through the negative pressure of the suction pipe, the respiratory secretion will be sucked out, commonly used in coma patients, or sputum excessive formation of phlegm thrombus obstruction of bronchial tubes, caused by respiratory difficulties. When there is always sputum after lung surgery, should be timely hospital consultation, active diagnosis and treatment. The above drugs need to be treated under the guidance of a doctor to avoid adverse consequences.