Yang deficiency is a common clinical syndrome in traditional Chinese medicine and is involved in many diseases, such as yang deficiency constitution, which is becoming more common. Furthermore, most late-stage disease will involve varying degrees of yang deficiency syndrome. Animal models of yang deficiency are mainly established according to three aspects: simulating the etiology of traditional Chinese medicine; western medicine pathology; and combining disease and syndrome, focusing on the spleen and kidney viscera. Studies of the essence and material basis of yang deficiency are performed according to two aspects: 1. physiological, biochemical, and molecular biology, including endocrine, immune, hemorheology, energy metabolism, free radicals, and trace elements; and 2. the level of genes, proteins, and metabolomics. These studies and method help us understand the pathogenesis of yang deficiency and its related diseases, perfect the diagnostic criteria of yang deficiency in different zang-fu viscera, and lay a foundation for the standardization of clinical treatment according to syndrome differentiation.