Fundamental　understanding　on　reaction　mechanism　of　a　working　Li/S　system　is　of　great　significance　to　design　better　batteries.　In　view　of　the　importance　of　lithium　polysulfides　(PSs)　in　the　working　process　of　battery,　PSs　saturated　solution　in　ethylene　glycol　dimethyl　ether/1,3-dioxolane　(DME/DOL)　was　synthesized　by　chemical　method.　The　properties　of　PSs　solution　were　studied　by　Tyndall　experiment,　UV-Vis　spectroscopy,　and　OCP-t　curve.　It　was　found　that　the　PSs　solution　is　heterogeneous.　PSs　and　S8　maintain　dynamic　equilibrium　through　disproportionation　reaction.　S8　generated　accounts　for　passivation　of　electrode.　Cyclic　voltammetry　of　S/C　electrode　under　different　fabrication　conditions　were　studied　by　using　three　electrode　system.　It　was　found　that　Li2S　generated　through　reduction　of　PSs　helps　to　dissolve　passive　layer　and　activates　electrode.　Passivation　is　more　serious　at　charge　stage.　Process　of　electrode　is　an　electron　transfer　reaction　accompanied　by　chemical　equilibrium.　A　novel　mechanism　based　on　precipitation　and　dissolution　of　S8　at　the　surface　of　electrode　is　used　to　elucidate　the　discharge-charge　process　of　Li/S　battery.　©　2021,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.