From the current background of lung cancer cases, the biggest cause of lung cancer is still smoking and second-hand smoke, followed by indoor air pollution, such as home renovation and oil smoke, and only after that is outdoor air pollution. Haze is mainly composed of three components: sulfur dioxide, carbon oxides and respirable particulate matter. It is true that haze can aggravate the burden of human respiratory tract and cause respiratory diseases such as acute respiratory infections, bronchitis, asthma, etc., but what is the relationship between haze and lung cancer? There are many harmful substances in haze, such as industrial emissions, car exhaust, dust, etc., many of which have carcinogenic activity. So, whether there is any relationship between haze and lung cancer or not, such a study needs a long observation time, and within this time, all we have to do is to pay attention to the hazards of haze and do a good job of protection on hazy days, even if it is not to prevent cancer, it is to protect our health. From the current background of lung cancer cases received, the biggest cause of lung cancer is still smoking and second-hand smoke, followed by indoor air pollution, such as home decoration and oil smoke, and only after that outdoor air pollution. However, we cannot deny that with the increasingly severe air quality, the incidence of lung cancer is indeed gradually increasing, showing a positive correlation. In severe haze days, people should go out less, wear masks if they have to go out, put some green plants indoors and use air purifiers.