Spleen-Stomach theory is an important constituent of the theoretical basis of Traditional Chinese Medicine (TCM), the Spleen here is not synonymous with the Spleen in western medicine anatomically, physiologically or pathophysiologically. Conceptually, Spleen-Stomach theory is a comprehensive one, it mainly involves the digestive system, its vegetative nervous system, immunologic function, hemopoiesis, muscle metabolism, endocrine function (thyroid, adrenal cortex and medulla), hepatic metabolic function, protein, nucleotide, energy, water and salt metabolism. Experimental researches on animal models and clinical studies on Spleen deficiency syndrome have yielded fruitful results in this field which lead to a better understanding of its mechanism and help open a new avenue for treatment of diseases relevant to Spleen deficiency.