In clinical practice, stratified sputum is mainly found in bronchiectasis, mainly due to chronic inflammatory infection of bronchi and surrounding lung tissues, accompanied by different degrees of airway obstruction, mucosal degeneration of bronchial walls, and destruction of bronchial smooth muscle, resulting in a persistent state of bronchial dilatation. The more obvious symptom is chronic cough, coughing up pus sputum, and the coughing up sputum placed in a container can appear in three layers, the upper layer is usually foamy sputum, the middle layer is plasma sputum, and the lower layer is a large amount of necrotic tissue fragments and a mixture of pathogens.