【】 Objective In this study, a mouse orthotopic lung cancer and lymph node metastasis model was established to simulate the lymph node metastasis during the occurrence and development of lung cancer, and to study the immune cells in the microenvironment before lung cancer metastasis. Methods Mouse Lewis lung cancer cells were cultured, and mouse lung orthotopic transplantation tumor models were constructed by injection through chest wall cells. Samples were taken at 7, 14, 21 and 28 days after tumor transplantation, and the changes of orthotopic transplantation tumor, lymph node tissue structure and B cells were observed by HE staining and immunohistochemistry. Results The orthotopic lung cancer model of C57BL/6J mice was successfully constructed, and the mediastinal lymph nodes were obtained according to the anatomical location. The changes of germinal center, lymphatic vessels and blood vessels in the lymph nodes, the structural changes of lymph nodes with tumor metastasis and the infiltration of tumor cells were observed with the development of lung cancer through HE staining. IHC results also showed an increase in lymph node B cells (CD19+) density in the model group. Conclusions The establishment of this model lays a foundation for the future study of immune cells, especially B cells, in the microenvironment of lung cancer before lymph node metastasis.