The purpose of this paper is to introduce Professor Liu Yanchi’s clinical experience in the treatment of lung cancer after operation with Ziyin Sanjie Prescription, a self-made formula, under the guidance of the academic thought of nourishing yin. It is considered that the etiology and pathogenesis of postoperative lung cancer is healthy qi deficiency and pathogenic factors excess mainly caused by dual damage of qi and yin. The essence of tumor is pathogenic heat in tradition Chinese medicine, which is easy to consume essential substances, blood, body fluid and healthy qi, and the deficiency of healthy qi is injured again after surgery. Although the tumor was removed after operation, there are still excess-pathogens such as phlegm and fluid in the body, which can easily lead to deterioration and other risks. The principle of treatment is reinforcing healthy qi as the key point, such as tonifying the spleen and replenishing the lung, that is to reinforcing the qi and yin of the spleen and stomach to generate the qi and yin of the lung, and dispelling pathogens as a supplement, such as resolving phlegm and softening hardness, dissipating bind and subduing swelling and regulating qi. The self-made Ziyin Sanjie Prescription on the basis of Xiaoluo Pills is used as the basic prescription for the postoperative treatment of lung cancer, and then modified according to different syndromes . And one proven case is presented.