A　series　of　bisimidazolium　tungstate　ionic　liquids　were　synthesized　and　applied　to　catalyze　the　reaction　of　ethylene　carbonate　(EC)　with　alcohols.　A　detailed　investigation　was　carried　out　on　the　relationship　between　catalyst　structures　and　catalytic　activities.　The　result　showed　that　1-butyl-3-methyl-bisimidazolium　tungstate　([Bmim](2)WO4)　containing　double　C-2-H　in　bisimidazolium　and　WO42-　had　more　effectively　catalytic　performance　than　other　bisimidazolium　tungstate　and　conventional　imidazolium　salt　(OAc-,　Cl-,　Br-).　Under　the　optimized　conditions　of　1:15　molar　ratio　of　EC　and　ethanol,　5　mol%　[Bmim](2)WO4,　85　degrees　C　and　0.5　h,　the　yield　of　diethyl　carbonate　(DEC)　was　nearly　100%.　The　detailed　DFT　calculations　and　NMR　spectroscopy　indicated　that　the　high　catalytic　activity　of　[Bmim](2)WO4　was　not　only　because　the　strong　nucleophilic　ability　of　WO42-　could　activate　ethanol,　but　also　the　special　structure　of　double　C-2-H　in　bisimidazolium　could　cooperatively　activate　EC.　The　reaction　was　catalyzed　by　synergistic　effect　in　double　C-2-H　and　WO42-　of　[Bmim](2)WO4.　In　addition,　[Bmim](2)WO4　could　be　used　seven　times　without　significant　loss　of　catalytic　activity.