There are many methods of sputum suction, the more commonly used ones are electric negative pressure suction catheter suction, electronic bronchoscopic suction and so on. 1. Electro-negative pressure suction catheter suction: when the patient is lying in bed for a long time or in critical condition, the sputum can not be discharged out of the body. For patients who have been lying in bed for a long time and the sputum is not easy to be coughed out, sputum can be suctioned by catheter of electric negative pressure suction device. 2. Fiberoptic bronchoscopic sputum aspiration: for patients with tracheotomy using ventilator-assisted respiration, sputum can be aspirated by tracheotomy; for patients with a lot of sputum that is not easy to be discharged, sputum can be aspirated by electronic bronchoscopy. Sputum suction may damage the mucous membrane of the respiratory tract, in the process of sputum suction needs to be extra careful, gentle action, to reduce the damage of sputum on the respiratory tract. The principle of asepsis should also be observed to avoid exacerbating lung infections. Nebulization can also be performed before sputum aspiration to promote the full expulsion of sputum. When sputum discharge is not smooth, it is recommended to consult a specialist in time.