Dimethyl　carbonate　(DMC)　is　an　important　chemical　raw　material　extensively　used　in　organic　synthesis,　lithium-ion　battery　electrolytes,　etc.　The　primary　method　for　industrial　synthesis　of　DMC　involves　transesterification　between　ethylene　carbonate　and　MeOH　but　faces　issues　with　difficult　catalyst　separation　and　low　catalytic　activity.　Based　on　the　synergistic　catalytic　activity　of　cation　and　anion,　this　study　develops　poly(ionic　liquid)s　of　[NXPIL][PHO]　and　[N3PIL][Y]　with　varying　alkaline　sites　and　alkalinity　levels.　This　is　accomplished　by　constructing　functional　polymer　monomers　containing　free　radical　polymerization　sites　and　nitrogen-containing　alkaline　groups,　and　by　polymerizing　them　with　suitable　cross-linking　monomers　in　a　specific　ratio　before　exchanging　the　resulting　polymers　with　different　anions.　Results　show　that　doping　with　nitrogen-containing　alkaline　groups　leads　to　enhanced　basic　functional　sites　while　appropriate　anions　provide　intensified　alkalinity　levels.　The　[N3PIL][PHO]　obtained　exhibits　superior　catalytic　activity　in　transesterification　synthesis　of　DMC,　with　a　yield　of　91.43%　and　selectivity　of　99.96%　at　a　reaction　time　of　2　h.　The　study　also　investigates　the　impact　of　poly(ionic　liquid)　cationic　structure　and　anion　types,　as　well　as　their　interactions,　on　catalytic　performance.　The　findings　reveal　that　the　catalytic　activity　of　poly(ionic　liquid)　is　restricted　by　the　interactions　between　cation　and　anion.　Based　on　these　findings,　a　possible　reaction　mechanism　was　proposed,　providing　theoretical　support　for　the　high-efficiency　production　of　DMC.