The chance of misdiagnosis of lung cancer is still relatively high in clinical practice because the complete diagnosis of lung cancer includes clinical diagnosis and pathological diagnosis. If a patient presents with cough, coughing sputum, blood in sputum, fever, chest pain, imaging suggests short burr, lobar, pleural depression sign, pleural traction sign, central type lung cancer manifesting as obstructive pneumonia, pulmonary atelectasis with large amount of pleural effusion, it is easy to diagnose lung cancer if imaging diagnosis alone is used. However, if thoracentesis and fiberoptic bronchoscopy are given and no malignant tumor cells are detected, this is a clinical diagnosis and lacks the basis for pathological diagnosis, which can easily lead to misdiagnosis. Without the results of histological examination, western doctors usually will not give radiotherapy, chemotherapy or even surgical treatment. Therefore, the diagnosis of lung cancer must be combined with clinical and cytohistological diagnosis before further examination and treatment, and there is a certain chance of misdiagnosis.