The lithium-sulfur battery(LSBs) is the most attractive candidate for the post lithium-ion battery technology because of it’s high theoretical energy density and low cost of active cathode material. However, recycling of LSBs will produce LiPSs and insoluble solid such as S8 and Li2S with low conductivity, which will damage the battery and even cause safety issue. What’s more, the LiPSs will cause the serious shuttle effect which will make the battery highly polarized and make it challenging for the application of the LSBs. In order to promote the performance of the LSBs, we start from the shuttle effect, discussed the adsorption capacity of Cs2F5Li3 on Li2S using binding energy which represents it’s capacity of restraining the shuttle effect in this article. By the first-principles method based on the density functional theory(DFT), we chose Cs2F5Li3, simulate experiments with it and Li2S in CASTEP and findout that their binding energy is -2.53eV. In order to explore their adsorption mechanism, we calculated the basic properties, including electronic structure, charge transferring of bulk phase Cs2F5Li3,bulk phase Li2S, Li2S(100), Cs2F5Li3(001) and the Cs2F5Li3（001）-Li2S（100）in this article. It is found that the binding energy is provided by the ionic bonds formed by Cs 5p, F 2p,F 2p, Li1s2s, S 3p, Li 1s2s and the covalent bonds formed by F 2p, S 3p. The result shows that Cs2F5Li3 can restrain the diffusion of LiPSs and the shuttle effect caused by Li2S. It can also relieve the low activity, the slow reaction kinetics and the severely capacity fading caused by Li2S. It has strong theoretical guidance for improving the performance of LSBs.