Old calcified foci in the left upper lung is a description of intrapulmonary lesions, which are stable foci in the lungs, and most of them do not have a significant impact on the physical condition. Infection, tuberculosis, trauma and other injuries to the lungs, calcium deposition occurs in the process of tissue repair, and eventually the lesion forms a stable calcified lesion, which occurs in the upper left lung and is diagnosed as old calcified foci in the upper left lung by CT examination. The corresponding lesions usually do not show obvious clinical symptoms and do not cause significant damage to the body. The presence of old foci in the left upper lung does not require much intervention, and the condition of the lungs can be reviewed annually by physical examination. Once obvious symptoms such as cough and chest pain appear, it is necessary to consult a doctor in time for observation and standardized treatment after confirming the condition.