Abstract: In recent years, paste technology has been rapidly promoted in domestic mines. It is a key technology for realizing green mining because it can effectively solve environmental and safety problems caused by mining. With the progress in science and technology, the research level of paste technology is constantly improving. Thickening technology of tailings is the primary procedure of paste backfill technology in metal mines, which can significantly improve the efficiency of tailings dewatering and utilization rate of tailings. Tailings thickening technology is an important part of the green development of mines. This paper presented a summary of the development process of tailings thickening and dewatering technology, dividing the development stage of the thickener into three: (1) ordinary thickener stage, (2) high-efficiency thickener stage, and (3) paste thickener stage. The application status of the thickening process of tailings and several typical application cases at home and abroad were also described. In addition, this paper explored different theories, including the single flocculation theory, multiple flocculation theory, bed compression theory under static/dynamic compression, and gravity thickening theory, along with the corresponding latest research progress of each theory. This paper also presented the main research methods of thickening of tailings, namely the static settlement experiment, small-scale thickening experiment, and semi-industrial thickening experiment. Advanced observational methods such as focused beam reflection measurement technology (FBRM) and particle video microscope technology (PVM) were also introduced. Moreover, the paper expounded on the research status of numerical simulation of tailings thickening technology and highlighted that the tailings thickening and dewatering technology is still in the development stage with some underlying problems, such as the instability of the key parameters of tailings thickening, the untimely production control of tailings thickening, and the imperfect information platform of tailings thickening. Overall, the development of tailings thickening technology is still facing numerous challenges. Finally, the direction of the development of tailing thickening technology is proposed in terms of personalization, automation, and intelligence.