Lung solid mucinous cell adenocarcinoma is a rare subtype of lung cancer, metastases from lung cancer to the endometrium are rare. The data of medical history and pathology of a case with lung solid mucinous cell adenocarcinoma with endometrial metastases were retrospectively analyzed, needle biopsies of the lung were solid mucinous cell adenocarcinoma, and adenocarcinoma were found in the endometrial pathology specimens. The results of immunohistochemical staining were consistent, and TTF-1 and CK7 were positive. It was diagnosed as the endometrial metastasis of lung solid mucinous cell adenocarcinoma, showing that lung solid mucinous cell adenocarcinoma could be metastasized to endometrium, and immunohistochemistry could provide a reliable basis for the diagnosis.