In　order　to　prevent　the　cracking　of　concrete　and　to　ensure　the　integrity　and　the　durability　of　the　structure,　it　is　important　to　control　temperature　and　thermal　stress.　The　finite　element　method　is　used　for　the　simulation　of　the　temperature　field　and　thermal　stress　of　large-sized　concrete　components.　It　is　shown　that　from　the　3rd　to　the　5th　day　the　concrete　reaches　the　highest　temperature.　From　the　7th　day,　the　domain　with　high　stress　appears　and　it　is　widely　distributed　in　the　stress　concentration　area.　After　that　time　it　reduced　gradually.　Accordingly,　the　state　of　the　temperature　and　thermal　stress　near　the　7th　day　should　be　critically　monitored.