For lung cancer detection, it is recommended for individuals over forty, especially smokers, to undergo a low-dose spiral CT for screening. Secondly, if someone has been a long-term heavy smoker and has undergone chest X-rays and low-dose spiral CT and a lung mass is found, it is suggested that the patient undergo a contrast-enhanced CT or a PET-CT to determine the condition and location of the lung mass. After establishing the condition and location, a sputum cytology test can be conducted. Thirdly, to confirm whether it is lung cancer, one should undergo bronchoscopy to obtain a biopsy, or a transthoracic lung puncture biopsy, or examine live tissue or metastatic lesions, or perform a pleural fluid examination to detect the cancer cells and determine the specific type of lung cancer to guide treatment. However, if the nature of the lesion cannot be clearly determined through mediastinoscopy, bronchoscopy, chest wall puncture biopsy, or other methods, a thoracotomy exploration is recommended. Additionally, the examination of tumor markers cannot be ignored.