Alveolar epithelial heterogeneous hyperplasia refers to the increase of alveolar epithelial cells at the level, the change of cell morphology and the disturbance of cell polarity, which generally belongs to the range of precancerous lesions. Alveolar epithelial heterogeneous hyperplasia is commonly seen in long-term chronic inflammatory stimulation and early stage of tumor. In long-term chronic inflammatory stimulation and early stage of tumor, the alveolar epithelium will show mild to severe hyperplasia of the cell-covered epithelium and loss of cell polarity, accompanied by the reduction of cellular components in the mesenchyme, which will lead to the heterogeneous hyperplasia of the epithelium. It should be noted that if alveolar epithelial hyperplasia occurs, it is necessary to cooperate with the doctor to complete the relevant examinations, to clarify the condition and standardize the diagnosis and treatment, to prevent the further development of alveolar hyperplasia.