The formation of lung cancer can be divided into external and internal causes. External causes, such as smoking and environmental pollution, can lead to lung cancer, but external causes must work through internal causes. The internal cause is that the immunity of the patient is low and the immune system loses the monitoring of tumor cells, which eventually forms tumor. From the perspective of Chinese medicine, the main causes of lung cancer are as follows: 1. coughing: all the five internal organs cause coughing, the heart, liver, spleen, lungs and kidneys may be dysfunctional, leading to low immunity, which in turn leads to the formation of lung cancer; 2. heart yang deficiency: i.e. not enough yang energy in the heart, often fear and dread, which in the long run will lead to immune dysregulation and tumor formation; 3. liver fire and temper tantrums, which finally damage the lung and lead to tumor; 4. It is suggested that in life, one must eat in moderation, live in a regular manner and keep a good mood to prevent the occurrence of tumors.