Abstract：Traditional Chinese medicine holds that obesity predominantly arises from improper dietary habits and is closely associated with excess pathogenic factors such as phlegm and blood stasis. Based on the theory "yang governs qi transformation，yin governs substance formation，" JI Yunxi proposes that obesity develops due to insufficient yangmediated qi transformation，where failure in transportation and metabolism is induced by spleen-kidney yang deficiency， leading to abnormal transformation of nutrients from food and water. Simultaneously，excessive yin-mediated substance formation constitutes a critical pathological link， characterized by endogenous accumulation of lipid-turbid-phlegmdampness and depletion of essence-blood， ultimately triggering yin-yang imbalance and establishing a pathological cycle. Consequently，the core therapeutic principle focuses on "supporting yang and suppressing yin，" with a fourfold approach： reinforcing yang to activate qi-transformation， removing dampness and eliminating turbidity， tonifying essence and blood，and ensuring qi activation.