To　mitigate　the　adverse　effects　of　residual　stress　and　deformation　during　high-power　laser　welding,　this　study　established　a　finite　element　model　based　on　thermodynamic　conditions　for　high-power　laser　welding　of　CLF-1　steel　for　nuclear　fusion　applications.　The　temperature　field　and　residual　stress　of　the　weld　were　simulated　by　using　the　composite　heat　source　model　together　with　Gaussian　model　and　conical　model.　The　results　showed　that　the　temperature　field　simulation　was　in　good　agreement　with　the　real　temperature　field.　The　simulation　results　of　the　weld　metal　(WM)　and　the　heat　affected　zone　(HAZ)　in　the　cross　sections　were　basically　consistent　with　those　of　the　real　cross　sections.　Moreover,　the　margin　of　error　between　the　simulation　results　and　the　real　data　was　&　LE;　1.3%　(the　largest　error　&　LE;0.04　mm).　The　Von　Mises　equivalent　stress　in　WM　was　distributed　irregularly,　and　its　largest　value　was　&　LE;　220　MPa;　the　equivalent　stress　declined　with　an　increase　in　distance　from　the　center　of　WM.　The　transverse　stress　distribution　in　the　center　of　WM　was　in　accordance　with　the　vertical　stress　distribution,　which　was　essentially　the　same　as　the　experimental　data　of　the　vertical　stress.　The　simulation　results　of　deformation　in　the　Z　direction　of　the　weld　showed　that　the　maximum　deformation　was　about　-0.2　mm　at　the　center　of　the　weld　corresponding　to　the　length　of　300　mm.　In　summary,　the　thermal　source　model,　combined　with　laser　welding　process　parameters,　can　provide　high-precision　prediction　of　stress　variations　and　deformation　control　during　the　actual　welding　manufacturing　process　of　the　test　blanket　module　(TBM)　structure.