Reactions　of　ethanol　+　hydroperoxyl　radical　(H?2)　are　well　known　a　crucial　reaction　class　in　oxidation　mechanism　of　ethanol.　However,　the　kinetic　parameters　of　the　reactions　are　basically　extrapolated　by　analogy　with　n-butanol　+　H?2　system　calculated　by　Zhou　et　al.　[1].　The　reliability　of　such　the　analogy　remains　to　be　seen,　as　no　directly　theoretical　or　experimental　evidence　is　available　in　literature　to　date.　In　this　study,　thermal　rate　coefficients　of　H-atom　abstraction　reactions　for　ethanol　+　H?2　system　were　calculated　at　both　CCSD(T)/cc-pVTZ//M06-2x/def-TZVP　and　CCSD(T)/CBS//M06-2x/def-TZVP　levels　of　theory,　with　an　uncertainty　of　a　factor　of　3,　by　means　of　using　both　conventional　transition-state　theory　and　canonical　variational　transition-state　theory.　Similar　to　n-butanol　+　H?2　system,　the　title　reactions　are　dominated　by　alpha　site　H-abstraction,　whereas　the　rate　coefficients　of　all　channels　of　ethanol　are　slightly　slower　than　that　of　n-butanol　+　H?2　system.　Generally,　the　new　calculations　show　only　limited　effect　on　ethanol　reactivity　at　low　pressures　and　high　temperatures　(over　1300　K)　but　it　prevents　the　kinetic　mechanisms　to　over-predict　ignition　delay　times　under　engine　relevant　conditions.　©　Asia-Pacific　Conference　on　Combustion,　ASPACC　2019.All　right　reserved.