Lung cancer is a common malignant tumor, the incidence of which has been increasing in recent years. Its typical symptoms are untreated cough, blood in sputum, dyspnea, chest pain and so on. With the extensive publicity of medical science over the years, most patients can draw their own and their family members’ attention when they have abnormal symptoms and go to the hospital in time. However, a few patients have special manifestations, such as not having respiratory symptoms such as coughing and hemoptysis, but having symptoms such as bone and joint pain, neck swelling, hidden pain in the upper abdomen, loss of appetite, and headache. They are often repeatedly seen in orthopedic surgery, physical therapy, and infectious disease departments. If the doctor lacks vigilance, it is very easy to lead to misdiagnosis and mistreatment, bringing irreversible consequences to the patient. 1.Patients with smoking history should think of the possibility of lung cancer even if they have no respiratory symptoms if they have unexplained bone and joint pain and headache. 2.Patients with untreated pneumonia in the same area for a long time should be alerted to the possibility of lung cancer. For patients who cannot be diagnosed clearly by chest X-ray and CT examination, fiberoptic bronchoscopy can be performed to help the diagnosis. 3.For those who are over 40 years old, it is better to have chest X-ray examination once a year if possible. 4.Patients with clinical manifestations resembling lung cancer but with normal chest X-ray should undergo further CT examination because CT is more sensitive than chest X-ray in detecting lung cancer. 5. Sputum exfoliative cell examination is simple, easy to perform and harmless to patients, so the role of this examination should be fully utilized to help make a clear diagnosis.