Two-dimensional　van　der　Waals　ferromagnetic　materials　hold　broad　prospects　in　spintronics　due　to　their　unique　physical　properties.　Interface　engineering　is　an　effective　method　to　tune　the　magnetic　properties　of　van　der　Waals　magnets　and　their　heterostructures.　In　this　study,　the　circular　photogalvanic　effect　(CPGE)　in　Fe3GeTe2　(1,　2,　4,　6　nm)/Bi2Te3　(8　nm)　heterostructures　was　systematically　investigated　to　reveal　the　relationship　between　the　interface　coupling　and　the　high-temperature　ferromagnetism.　While　both　the　top　Fe3GeTe2/Bi2Te3　interface　and　the　Bi2Te3　bottom　surface　may　contribute　to　the　observed　CPGE　current,　the　former　was　confirmed　to　be　the　dominant　driver　for　a　Fe3GeTe2　thickness　larger　than　2　nm.　A　significant　spin–orbit　coupling　effect　was　found　to　be　present　at　the　Fe3GeTe2/Bi2Te3　interface　and　it　plays　a　substantial　role　in　defining　the　CPGE　current.　By　combining　magnetotransport　and　CPGE　measurements,　we　identified　interfacial　exchange　coupling　as　the　key　mechanism　for　the　enhanced　Curie　temperature　(TC)　in　FGT/BT　heterostructures　relative　to　pure　FGT　of　equivalent　thickness.　This　work　highlights　the　importance　of　interfacial　interactions　in　tuning　physical　properties　of　van　der　Waals　magnet/topological　insulator　heterostructures,　with　CPGE　serving　as　a　sensitive　probe　of　these　effects,　and　paves　the　way　for　utilizing　such　interactions　in　magnetic　and　topological　state　control.　©　2025　Elsevier　B.V.