Converting　CO2　into　chemicals　with　electricity　generated　by　renewable　energy　is　a　promising　way　to　achieve　the　goal　of　carbon　neutrality.　Carbon-based　materials　have　the　advantages　of　low　cost,　wide　sources　and　environmental　friendliness.　In　this　work,　we　prepared　a　series　of　boron-doped　covalent　triazine　frameworks　and　found　that　boron　doping　can　significantly　improve　the　CO　selectivity　up　to　91.2%　in　the　CO2　electroreduction　reactions(CO2RR).　The　effect　of　different　doping　ratios　on　the　activity　by　adjusting　the　proportion　of　doped　atoms　was　systematically　investigated.　This　work　proves　that　the　doping　modification　of　non-metallic　materials　is　a　very　effective　way　to　improve　their　activity,　and　also　lays　a　foundation　for　the　study　of　other　element　doping　in　the　coming　future.