In　order　to　obtain　the　deflection　and　bending　analytical　solution　about　concrete　rectangular　thin　plate　(RTP)　of　three　clamped　sides　and　one　free　side,　in　this　paper,　based　on　the　small　deflection　plate　theory　and　superposition　principle,　considering　temperature　variation　which　is　perpendicular　to　surface,　the　RTP　of　three　clamped　sides　and　one　free　side　under　temperature　disparity　is　regarded　as　under　the　superposition　of　temperature　disparity　and　the　bending　moment　with　three　adjacent　sides.　Firstly,　by　supposing　deflection　function　which　has　undetermined　parameter　at　free　side,　and　adopting　Levy　method,　the　closed　solution　about　the　RTP　under　free　boundary　constraints　is　obtained;　Secondly,　the　closed　solution　under　temperature　disparity　is　obtained;　Thirdly,　using　the　solution　of　RTP　with　four　simply　supported　sides　under　the　bending　moment　on　three　adjacent　sides,　the　solution　of　RTP　with　three　simply　supported　sides　and　one　free　side　under　the　bending　moment　on　three　adjacent　sides　is　obtained;　Finally,　the　deflection　and　bending　analytical　solution　about　RTP　of　three　clamped　sides　and　one　free　side　under　temperature　disparity　is　acquired　adopting　the　superposition　principle,　and　calculation　coefficient　table　about　concrete　RTP　of　three　clamped　sides　and　one　free　side　under　temperature　disparity　is　obtained　using　MATLAB.　And　so　a　theory　calculation　base　about　concrete　RTP　with　three　clamped　sides　and　one　side　free　under　temperature　disparity　in　engineering　structure　is　provided　for　engineering　design.