In many cases of thoracic surgery, pulmonary function tests are routinely performed before surgery to assess whether the patient can tolerate the surgery, or, in layman’s terms, whether there are enough lungs left after the operation. Pulmonary function tests are important, but they are not necessarily a dogmatic decision to operate based on the results. Recently, we had a 72-year-old male patient with lung tumor who had been smoking for a long time, and the preoperative examination revealed that the lung function was very poor, with only 0.9 liters of spirometry in the first second, which, according to the textbook knowledge, makes even open-heart surgery very dangerous. According to textbook knowledge, even open-heart surgery is dangerous for this kind of patient. Once the lungs are cut after surgery, there may not even be a way to stop using the ventilator. But in this patient, we not only did the surgery, but also did a minimally invasive thoracoscopic lobectomy. In the middle of the operation, we saw that the lung condition was really poor, and the emphysema was very strong. However, the surgery was completed successfully and the recovery was good.