The shuttling of polysulfides is a major issue that tackles the practical use of Li–S battery. Recently, the catalysis of polysulfides has been developed as an effective solution to accelerate the polysulfideconversion and reduce the shuttle effect fundamentally. In this chapter, the origin and the research progress of catalysis in Li–S batteries are presented systematically. We start with the redox chemistry of polysulfides and introduce the importance of catalysis in Li–S battery. Subsequently, promising catalytic materials are categorized according to their composition and functions. Moreover, key parameters that can precisely describe the catalytic mechanisms are proposed following by the summary of advanced characterizationtechniques for better demystifying the catalysis process, which is urgently needed for establishing a systematic research protocol for the catalysis in Li–S battery. Finally, perspectives are given for the rational design of high-efficiency catalytic materials and promoting the practice use of Li–S battery.