The causative factors of lung adenocarcinoma include heredity, which has some chance of being inherited, but is not a genetic disease. The cause of lung cancer has not been clearly defined so far, and if there is someone in the family who has lung cancer, then the individual has an increased risk of developing lung cancer. Other factors include smoking, occupational exposure, air pollution, ionizing radiation, diet and physical activity. Among them, smoking is the most common cause of lung cancer, and about 85% of lung cancer patients have a history of smoking. Lung adenocarcinoma is highly prevalent in people aged 55-65 years, and the incidence rate of urban residents is higher than that of rural areas, which may be related to the higher level of carcinogenic substances in air pollution and soot. There are carcinogenic substances such as benzo(a)pyrene, arsenous oxide, radioactive substances, nickel, chromium compounds, sulfur dioxide (SO2), nitric oxide (NO), and non-combustible aliphatic hydrocarbons in industrial exhaust and automobile exhaust in cities. Staying away from tobacco is the key to lung adenocarcinoma prevention. Adults should take the initiative to quit smoking, and teenagers should develop good living habits and stop smoking; and consult the doctor promptly if they feel unwell.