In　an　attempt　to　improve　the　flexural　bearing　capacity　and　deformation　capacity　of　the　stone　in　the　existing　stone　structure　and　thereby　to　prevent　the　fragility　of　the　stone　from　being　damaged.　This　paper　puts　forward　the　strengthening　technology　of　bonded　steel　for　flexural　strengthening　of　existing　stone　slabs　and　carries　out　bending　capacity　tests　to　study　the　effect　of　the　thickness　and　width(sectional　area)　of　the　reinforced　steel　plate　on　the　bending　behaviors　of　the　stone　slabs.　The　results　showed　that　the　brittle　failure　pattern　of　stone　slab　could　be　significantly　and　effectively　improved　by　steel　bonding　reinforcement　and　the　destructive　pattern　is　ductile　fracture　with　obvious　flexural　deformation.　The　flexural　bearing　capacity　of　bonded　steel　strengthened　slabs　was　significantly　improved,　and　the　ultimate　load　was　60%　~　233%　higher　than　that　of　unreinforced　slabs.　With　the　increasing　of　the　thickness　and　width　of　steel　plates,the　effect　of　promoting　the　bearing　capacity　of　slabs　was　more　significant.　Steel　bonded　stone　slabs　can　effectively　suppress　the　development　of　invisible　micro　cracks　in　the　tensile　area,significantly　improving　the　ultimate　tensile　strain　capacity　at　the　bottom　of　the　slabs,and　thus　increase　the　cracking　load　of　stone　slabs.With　the　increasing　of　the　thickness　and　width　of　the　steel　plate,and　compared　with　the　unreinforced　stone　slab,the　ultimate　tensile　strain　of　the　stone　increased　to　79.75%　~　178.48%,　and　the　cracking　load　of　the　reinforced　stone　slab　increased　by　60%　~　140%.　Finally,　through　theoretical　calculation,　the　calculation　formula　of　flexural　capacity　of　stone　strengthened　with　bonded　steel　was　established,　and　the　theoretical　calculation　results　were　in　good　agreement　with　the　experimental　results.　©　2023　Editorial　Board　of　Journal　of　Basic　Science　and.　All　rights　reserved.