Abstract： This article introduces Professor LI Weilin's clinical experience in treating pulmonary nodules. Given the diagnostic challenges in differentiating benign from malignant nodules and the required long-term follow-up， pulmonary nodules present significant clinical difficulties. Professor LI Weilin views this condition as deficiency interweaved with excess syndrome，characterized by the accumulation of phlegm，blood stasis，and toxins in the lung collaterals. The treatment approach should simultaneously address phlegm resolution， stasis removal， detoxification， deficiency supplementation，and collateral unblocking to eliminate pathogens. The core therapeutic principle follows the "left ascending and right descending" movement of qi，blood，yin，and yang，while regulating the liver，spleen，and lungs to unblock lung collaterals and expel pathogens. The "left ascending and right descending" theory posits that the liver stores blood and governs ascending movement （yang leading yin） to propel blood with qi，while the lungs govern qi and control descending movement （yin leading yang） to direct turbid yin downward. Yin and yang circulate throughout the body with yang qi ascending leftward and yin qi descending rightward. Based on this theory， Professor LI Weilin modifies classical formulas including Xiao Chaihu Decoction，Guizhi Decoction，Shengjiang Powder，Biejia Jian Pills， and Erchen Decoction. These prescriptions combine ascending and descending herbs to promote yang ascent and yin descent， restore internal-external harmony， guide phlegm-stasis-toxin elimination through qi movement， expelling pathogens to the exterior，and unblock lung collaterals，thereby pulmonary nodule can dissipate.