In　this　study,　the　effect　of　Fe　addition　on　microstructure　evolution　and　grain　refinement　mechanism　during　hot　deformation　of　new　Ti-6Al-4V-xFe　(x　=　0–0.9　wt%)　alloys　were　investigated.　The　peak　stress　showed　a　decreasing　trend,　and　the　microstructure　presented　obvious　grain　refinement　with　the　increase　of　Fe　content.　The　flow　softening　behavior　was　contributed　by　dynamic　recovery　(DRV)　and　dynamic　recrystallization　(DRX).　The　average　grain　size　decreased　from　52.2　μm　to　11.3　μm,　and　the　fraction　of　the　high　angle　grain　boundary　(HAGB)　increased　from　66.49%　to　76.33%　when　Fe　concentration　increased　from　0　wt%　to　0.9　wt%.　Fe　addition　also　facilitated　in　the　annihilation　of　the　dislocations,　which　resulted　in　a　decrease　in　the　average　ρGND　density.　The　high　Schmid　factor　(＞0.45)　content　increased　with　the　Fe　content　in　the　basal　slip　(0001)　and　prismatic　slip　{101¯1}　of　the　α　phase,　as　well　as　in　the　{112¯}　and　{123¯}　slip　systems　of　the　β　phase.　All　evidence　indicated　that　Fe　addition　promoted　the　hot　workability　of　the　Ti-6Al-4V-xFe　(x　=　0–0.9　wt%)　alloys　and　refined　the　grain　size　during　hot　deformation.　©　2021　The　Author(s)