Abstract: The Janus kinases (JAK) modulate the signal transduction of cytokines such as interleukins (IL) and interferons (IFN) through Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway. JAK inhibitors can be used to treat autoimmune diseases, however, due to the narrow therapeutic index and immunosuppression, researchers turned to tyrosine kinase 2, which is involved in the signal transduction of IL-23, IL-12 and type I IFNs as a member of the Janus kinases. Selective tyrosine kinase 2 inhibitors could reduce the occurrence of side-effects and are more secure in clinic, so the research on selective TYK2 inhibitors in autoimmune diseases have further developed and deepened. Herein, we reviewed the structural characteristics, mechanism, signaling transduction pathways and the development process of selective TYK2 inhibitors to provide reference for the research on metabolic disease drugs.