Two　methods　to　calculate　transient　thermal　strain　(TTS)　of　concrete　at　high　temperature　are　presented.　They　are　modifying　thermal　expansion　coefficient　and　modifying　elastic　coefficient　of　concrete.　First,　a　user　thermal　expansion　coefficient　subroutine　is　coded　to　calculate　TTS　by　using　ABAQUS.　Then,　the　calculation　of　TTS　is　realized　by　modifying　the　elastic　coefficients　of　concrete　on　the　basis　of　reasoning.　The　results　of　calculated　samples　show　that　the　two　methods　are　reasonable.