Lung cancer is not contagious, but there is some family susceptibility. Lung cancer belongs to common respiratory malignant tumors, most of which are caused by decreased function of immune system and gene mutation. Infectious diseases need to have infectious sources and transmission routes, etc. Lung cancer does not have infectious conditions. Lung cancer does not have infectious conditions, so it is not contagious and does not belong to infectious diseases. However, lung cancer has certain genetic susceptibility. Therefore, families with lung cancer patients should do a good job of prevention, develop good living habits and have regular medical checkups to detect the disease at an early stage. After diagnosis, lung cancer patients should keep a good mindset, actively cooperate with doctor’s treatment, ensure enough nutrition and proper physical exercise to prolong their life and quality of life. If they feel sick, they should consult doctor in time.