The degree of differentiation of lung adenocarcinoma is mainly based on the degree of difference between lung adenocarcinoma cells and normal tissue cells. Generally, the greater the difference between adenocarcinoma cells and normal lung tissue cells, the less differentiated the lung adenocarcinoma is, which is a low-grade lung adenocarcinoma, while if the difference between cancer cells and normal tissue cells is smaller, the better differentiated the lung adenocarcinoma is, which is a high-grade lung adenocarcinoma. Theoretically, the higher the grade, the closer the adenocarcinoma is to the higher grade. The prognosis for high-grade adenocarcinoma is better than that for low-grade adenocarcinoma. However, regardless of the degree of differentiation, the treatment of lung adenocarcinoma is mainly based on the presence or absence of genetic mutations, as well as the stage of lung adenocarcinoma, tumor size, and lymph node metastasis, and the degree of differentiation is only used as a reference to some extent.