Ordinary people hope to achieve early detection and diagnosis of lung cancer by paying attention to the early symptoms of lung cancer, but this is very difficult. 1. Early stage lung cancer is usually asymptomatic and mostly found through chest X-ray or CT during physical examination, while once there are symptoms, it is often in the middle to late stage. Therefore, regular physical examination should be emphasized, especially for people with high risk factors of lung cancer (such as smoking, family history, working in dusty environment, etc.). 2.Symptoms of lung cancer are not only related to the stage but also related to the location of the tumor (whether it is peripheral or central). Relatively speaking, the symptoms of peripheral type lung cancer appear later than central type. The common symptoms include cough (non-irritating cough), blood in sputum (blood or blood clots), hemoptysis (small mouthful of fresh blood or mixed with blood clots), chest pain (more specific location and more persistent), etc. Especially for people who have a bad habit of smoking they must pay attention to the two symptoms of cough and blood in sputum. If the above symptoms appear, you should seek medical attention promptly and not just take some “cold medicine” or “anti-inflammatory medicine” by yourself. On the other hand, the above mentioned symptoms are not specific, that is to say, if you have these symptoms, it may not necessarily be lung cancer, but also lung inflammation, tuberculosis, branched expansion, etc. Therefore, if you have these symptoms, the best way is to consult a doctor in time, so that you can reduce unnecessary worries and anxiety.