In　this　paper,　the　total　ionizing　dose　(TID)　response　of　body-on-insulator　(BOI)　FinFETs　is　investigated　and　compared　with　bulk　Si　FinFETs　by　3D　TCAD　simulation.　The　irradiation　induced　off-state　leakage　current　(I-off)　is　significantly　reduced　by　the　localized　oxide　layer　in　the　sub-fin　region　of　BOI　FinFETs.　The　I-off　of　BOI　FinFETs　increases　negligibly　after　irradiation.　In　contrast,　the　I-off　of　bulk　Si　FinFETs　with　the　same　geometry　increases　by　several　times　after　irradiation.　Besides,　BOI　FinFETs　show　weaker　dependence　on　fin　width,　and　the　off-state　leakage　current　of　bulk　FinFETs　induced　by　TID　irradiation　increases　significantly　with　the　decrease　of　fin　width.　Moreover,　with　the　scaling　of　gate　length,　the　I-off　of　BOI　FinFETs　remains　almost　unchanged,　while　it　increases　by　more　than　an　order　of　magnitude　for　bulk　FinFETs,　which　indicates　that　BOI　FinFETs　show　strong　scaling　capability　in　terms　of　TID.　Therefore,　BOI　FinFETs　demonstrate　strong　TID　tolerance　and　scaling　capability,　and　have　great　potential　for　application　in　radiation　environment.