Lung mucinous adenocarcinoma is a kind of lung adenocarcinoma, which is a special type of lung malignant tumor. Early clinical manifestations of lung mucinous adenocarcinoma include cough, hemoptysis, shortness of breath or wheezing, and some patients may have vague pain in the chest, fever, weight loss, and dyspnea. Although the above clinical symptoms may appear in the early stage of mucinous adenocarcinoma, the early clinical manifestations of mucinous adenocarcinoma are not specific and not easy to be detected, and most of the patients are already in the middle or late stage when they are detected, with localized spread or metastasis. Lung mucinous adenocarcinoma tends to grow out of the lumen, and may invade blood vessels and lymphatic vessels in early stage, and often metastasize before causing symptoms of carcinoma in situ. In the early stage of mucinous adenocarcinoma, there is no specific finding in CT examination, and there may be hairy glass nodules or shadows, but the confirmation of the diagnosis needs to rely on pathological biopsy. If early symptoms of mucinous adenocarcinoma of lung appear, patients should consult doctor in time and do relevant examination and treatment under doctor’s guidance, so as to avoid delaying the condition.