The　conversion　of　CO2　into　value-added　chemicals　has　become　an　imminent　research　topic　and　the　cycloaddition　of　CO2　with　a　C1　resource　to　produce　cyclic　carbonates　is　a　promising　pathway　for　CO2　utilization.　Herein,　a　series　of　POSS-based　polyionic　liquids　(PILs)　were　synthesized　by　the　copolymerization　of　octavinyl　polyhedral　oligomeric　silsesquioxane　(POSS)　with　an　imidazolium　ion　linker.　The　prepared　PILs　have　the　characteristics　of　hydrogen　bond　donors,　halogen　atom　sites,　stable　pore　structures,　and　thermal　stability,　and　are　used　as　heterogeneous　catalysts　for　the　cycloaddition　of　epoxides　with　carbon　dioxide.　The　effect　of　linkers　on　the　cycloaddition　is　investigated　by　tuning　the　ratio　of　POSS　units　to　imidazolium　ions.　Under　the　optimized　conditions,　the　conversion　of　epichlorohydrin　can　reach　99.18%　at　atmospheric　pressure　with　neither　co-catalysts　nor　solvents.　It　is　concluded　that　the　reaction　of　the　cycloaddition　of　epoxides　with　carbon　dioxide　follows　pseudo-first-order　kinetics.　Moreover,　the　presence　of　the　catalysis　of　PILs　leads　to　a　significant　decrease　in　the　activation　energy　barrier　for　cycloaddition.　The　catalyst　can　be　facilely　recovered　due　to　its　high　stability,　and　only　a　slight　decrease　in　conversion　was　observed　after　five　successive　runs.　In　addition,　the　mechanism　of　PILs　catalyzing　the　cycloaddition　reaction　of　epoxides　with　CO2　is　proposed.　This　work　not　only　provides　a　sustainable　and　green　process　for　CO2　cycloaddition,　but　also　highlights　the　potential　of　using　PILs　for　CO2　utilization.　©　2023　The　Royal　Society　of　Chemistry.