By　studying　the　microstructure　and　microhardness　of　the　laser　additive　repair　of　directionally　solidified　superalloy　DZ125L　under　an　induction　heating　condition,　the　effect　of　induction　heating　on　the　formation　mechanism　of　microstructure　and　the　evolution　of　mechanical　properties　near　the　interface　between　repair　layers　and　substrate　is　revealed.　The　results　show　that　induction　heating　at　1　000　can　effectively　reduce　the　temperature　gradient　in　comparison　with　the　sample　without　induction　heating.　As　a　result,　in　repair　layers,　the　primary　dendrite　arm　spacing　increases　from　3.8　μm　to　7.2　μm,　γ＇　particles　grow　from　19.8　nm　to　74.0　nm,　and　the　heat　affected　zone(HAZ)　extends　from　200　μm　to　500　μm.　The　microhardness　continuously　increases　in　the　HAZ　and　reaches　a　plateau　in　the　repair　layers.　The　increased　microhardness　in　the　HAZ　is　mainly　attributed　to　the　volume　fraction　change　of　primary　and　secondary　γ＇　precipitates,　whereas　the　hardening　mechanism　in　the　repair　layers　is　related　to　the　γ＇-size-dependent　strengthening　effect.　©　2021　Journal　of　Mechanical　Engineering.