Lung carcinoma in situ life expectancy is related to the pathological type of carcinoma in situ, treatment method and whether it is metastasized or not. Generally speaking, after timely detection and active cooperation with doctors, the 5-year survival rate can reach more than 70%. The actual survival time is related to individual’s physical condition and disease progression. Adenocarcinoma in situ of lung belongs to early stage lung cancer, surgical resection is preferred after diagnosis, generally patients have good prognosis and their survival is almost unaffected; small cell lung cancer belongs to the more invasive type of pathology, metastasis of the tumor can occur in the early stage, and after surgical resection of the lesion, radiotherapy, chemotherapy, etc. are needed, but patients’ life expectancy is likely to be no longer than 5 years. It should be noted that lung cancer patients can reduce the adverse effects of the disease through “early detection, early diagnosis and early treatment”, and it is recommended that patients build up confidence and actively cooperate with doctors for treatment.