Ferritic/martensitic　steel,　with　Cr　atomic　content　in　a　range　of　7%-15%,　is　a　promising　candidate　for　advanced　nuclear　power　systems,　due　to　its　swelling　resistance　and　creep　fracture　resistance　under　irradiation.　Under　thermodynamic　conditions,　Cr　segregation　usually　occurs　at　grain　boundary　(GB)　in　Fe-Cr　alloys.　However,　irradiation　can　greatly　accelerate　this　process.　The　enrichment　of　Cr　at　GB　will　enhance　precipitation,　resulting　in　embrittlement;　while　the　depletion　of　Cr　at　GB　may　greatly　weaken　the　corrosion　resistance　properties.　In　the　present　work,　thermodynamic　segregation　and　radiation-enhanced　segregation　of　Cr　element　at　GB　in　Fe-Cr　alloy　is　investigated　by　using　the　Wheeler-Boettinger-McFadden　(WBM)　phase-field　model.　The　simulation　results　show　that　temperature　has　a　great　influence　during　thermodynamic　segregation　of　Cr　at　the　GB　without　radiation:　when　the　temperature　is　lower　than　500　the　segregation　amount　of　Cr　at　the　GB　is　relatively　small;　when　the　temperature　is　higher　than　500　the　Cr　concentration　at　GB　increases　significantly.　In　addition,　as　the　concentration　of　Cr　in　the　matrix　increases,　the　amount　of　relative　increase　of　Cr　concentration　at　GB　decreases.　However,　the　Cr　concentration　at　GB　under　irradiation　is　significantly　enhanced,　compared　with　the　counterpart　without　irradiation.　With　the　increase　of　dose　rate,　the　Cr　concentration　in　the　center　of　GB　also　increases.　Moreover,　with　the　increase　of　Cr　concentration　in　the　matrix,　the　relative　increase　of　the　Cr　concentration　at　the　GB　weakens.　©　2021　Chinese　Physical　Society.