Pressure　resistance　welding　is　usually　used　to　seal　the　connection　between　the　cladding　tube　and　the　end　plug　made　of　zirconium　alloy.　The　seal　welded　joint　has　a　direct　effect　on　the　service　performance　of　the　fuel　rod　cladding　structure.　In　this　paper,　the　pressure　resistance　welded　joints　of　zirconium　alloy　tube-plug　structure　were　obtained　by　thermal-mechanical　simulation　experiments.　The　microstructure　and　microhardness　of　the　joints　were　both　analyzed.　The　effect　of　processing　parameters　on　the　microstructure　was　studied　in　detail.　The　results　showed　that　there　was　no　β-Zr　phase　observed　in　the　joint,　and　no　obvious　element　segregation.　There　were　different　types　of　Widmanstätten　structure　in　the　thermo-mechanically　affected　zone　(TMAZ)　and　heat　affected　zone　(HAZ)　of　the　cladding　tube　and　the　end　plug　joint　because　of　the　low　cooling　rate.　Some　part　of　the　grains　in　the　joint　grew　up　due　to　overheating.　Its　size　was　about　2.8　times　that　of　the　base　metal　grains.　Due　to　the　high　dislocation　density　and　texture　evolution,　the　microhardnesses　of　TMAZ　and　HAZ　were　both　significantly　higher　than　that　of　the　base　metal,　and　the　microhardness　of　the　TMAZ　was　the　highest.　With　the　increasing　of　welding　temperature,　the　proportion　of　recrystallization　in　TMAZ　decreased,　which　was　caused　by　the　increasing　of　strain　rate　and　dislocation　annihilation.　©　2023　Korean　Nuclear　Society