Based　on　an　concrete　＂T＂　beam　model　test,　the　distributions　of　its　inner　temperature　in　the　natural　environment　and　the　corresponding　thermal　displacement　are　tested,　with　tens　of　thousands　of　measured　data　obtained.　Through　the　analysis　of　data　collected　by　mathematical　statistics,　the　modified　coefficient　of　the　formula　(Delta　L=alpha　x　Delta　t　x　L)　computing　the　thermal　displacement　of　concrete　bridge　is　brought　out.　And　the　FEM　thermal　analysis　is　taken　But　there　is　much　difference　between　the　test　data　and　the　computing　results　with　shrinkage　distortion　generated　by　the　change　of　the　dampness　according　to　the　code　has　been　eliminated.　The　researching　results　mentioned　above　provide　the　base　to　computing　the　thermal　deformation　of　the　concrete　T　beam　with　Jointless　Bridge,　and　provide　the　reference　to　computing　the　thermal　deformation　of　other　sectional　concrete　bridge.