Smoking is a clear risk factor for lung cancer, but there is no specific clinical data on the incidence rate, which should be analyzed in the context of individual physical condition, duration of smoking and amount of smoking. If you have been smoking for a long time, and the amount of cigarettes you smoke every day is relatively large, and you are often exposed to second-hand smoke, you are very likely to get lung cancer, and the chances of getting lung cancer are higher than that of non-smokers. Cigarettes contain a large amount of nicotine and other harmful substances, if long-term smoking, or long-term exposure to second-hand smoke, it will lead to toxic objects into the body, easy to repeatedly stimulate the bronchial tubes, lung tissues, and alveoli, when the mucous membrane breaks down, it is easy to weaken the elasticity of the wall, resistance to decline, and ultimately likely to cause epithelial cell hyperplasia, and the proliferation of the formation of a period of time, it is easy to develop into lung cancer, but the specific chances depend on the individual’s physical condition and the ability of the individual to get lung cancer. The specific chance depends on the individual’s physical condition as well as the time and amount of smoking. In order to reduce the incidence of lung cancer, one should reduce the amount of smoking and stay away from second-hand smoke to avoid increasing the incidence.