The　hydration　degree　of　binders　and　cement　is　investigated　by　measuring　the　adiabatic-temperature　rise　of　concrete　at　low　water-binder　ratio　with　different　fly-ash　content.　The　results　denote　that,　with　a　constant　water-binder　ratio,　both　of　the　hydration　degree　of　binders　and　that　of　cement　decrease　with　the　increasing　fly-ash　content　in　the　early　stage.　In　a　later　stage,　however,　the　hydration　degree　of　cement　increases　with　the　increasing　fly-ash　content　and　the　hydration　degree　of　binders　peaks　when　the　fly-ash　content　is　35%.　Fly　ash　is　one　of　the　mineral　admixture　of　which　high-performance　concrete　is　made　up.　It　brings　down　the　rise　of　concrete　temperature　significantly　and　helps　solve　the　problems　of　shrinkage　and　crack　of　concrete　structure.　Because　the　hydration　mechanism　in　common　concrete　is　different　from　that　in　concrete　with　low　water-binder　ratio,　and　the　hydration　environment　is　different　between　concrete　and　cement　pastes,　to　determine　the　adiabatic-temperature　rise　of　concrete　directly　conforms　to　the　actual　situation.　The　adiabatic-temperature　rise,　adiabatic-temperature-rise　rate,　hydration　degree　of　both　binders　and　cement　are　investigated　by　measuring　adiabatic-temperature　rise　of　concrete　with　different　fly-ash　content.　©　(2011)　Trans　Tech　Publications,　Switzerland.