The　study　examines　the　interactions　of　the　energy　R&D　investments　and　the　CO2　abatement　policy　using　an　endogenous　energy　R&D　climate-economy　model.　Energy　R&D　investments　affect　the　carbon　emissions　directly　through　efficiency　improvements　and　indirectly　by　changing　the　comparative　advantages　of　resources.　This　study　considers　the　R&D　investments　in　energy　efficiency　and　low-carbon　technology　and　explores　how　energy　R&D　investments　accelerate　the　energy　transition　from　fossil　fuels　to　low-carbon　technology.　Three　policies　of　carbon　abatements　are　considered,　namely,　the　optimal　policy,　the　2　degrees　C　policy,　and　the　1.5　degrees　C　policy.　From　the　perspectives　of　benefits　and　costs,　the　optimal　policy　leads　to　the　least　abatement　costs　compared　to　the　other　two　abatement　policies.　This　study　indicates　that　the　more　restrictive　the　abatement　policy　is,　the　more　severe　economic　damage　is　caused　in　the　short　run.　but　more　economic　welfare　is　gained　in　the　long　run.