Abstract: “Robust spleen system expelling putrid waste” originates from Treatise on Cold Damage, and its core meaning lies in the fact that when the spleen and stomach functions are robust, putrid waste will naturally be eliminated. Master of Traditional Chinese Medicine Pi Chiheng offers an innovative interpretation of this classic theory: on the one hand, he systematically expounded the physiological functions of the rise and fall, reception and transformation, dryness and dampness of spleen and stomach qi; on the other hand, he provides a scientific explanation from the perspective of the modern “gut-kidney axis” mechanism. He also points out that although diabetic kidney disease (DKD) affects the kidneys, the spleen is crucial. He proposes that “spleen deficiency, yang deficiency and yin depletion, and accumulation of putrid waste” are the core pathogenesis of DKD. Among these, spleen deficiency is the initial stage of the disease, yang deficiency and yin depletion are the key to its progression, and the accumulation of putrid waste is the final result. Clinical diagnosis and treatment are based on the fundamental principle of “balancing and unblocking the spleen and stomach qi transformation, and eliminating putrid waste and stagnation”. This leads to four major diagnostic approaches: balancing and regulating the pivot to restore the rise and fall, harmonizing the circulation of Ying Wei to regulate the entering and leaving, strengthening the fire and earth to aid the reception and transformation, and regulating water and fire to balance dryness and dampness. This has formed the formation of distinctive compatibility rules and representative drug pairs based on the yin-yang theory of the spleen system, providing new ideas and references for the traditional Chinese medicine diagnosis and treatment of DKD.