Tablet in tablet technology, as a new type of drug formulation technology, uses a specific pressing process to wrap the active ingredient or drug containing layer in the middle, and the outer layer is covered with one or more coating layers with different functions such as protection, sustained and controlled release, isolation, etc.. Tablet in tablet technology endows drugs with unique drug release and functional characteristics through special preparation processes and structural design, thereby achieving precise regulation of drug release, enhancing drug stability, and improving other drug properties. In recent years, it has received widespread attention. This article summarizes the development history, principles, and characteristics of tablet in tablet technology through relevant literature research. It also elaborates on the innovative applications of tablet in tablet technology and explores pharmaceutical research, in order to provide some references for the research and development of such formulations.