Transition　metal　oxides　ZnO　and　Cu2O　are　widely　used　in　solar　driven　photocatalytic　water　splitting　for　hydrogen　production　by　their　hetero-composites.　Charge　transfer　on　the　interfacial　heterojunctions　is　the　most　important　responsible　mechanism.　However,　direct　photophysical　indications　for　the　formation　of　heterojunctions　and　for　the　charge-transfer　dynamics　on　the　Cu2O/ZnO　interfaces　have　not　been　reported.　We　investigate　in　this　work　transient　absorption　(TA)　spectroscopic　signatures　for　the　hetero-interfacial　charge-transfer　process　from　Cu2O　to　ZnO　using　femtosecond　pump　probe.　Comparing　the　TA　spectroscopic　response　of　the　Cu2O/ZnO　nanocomposites　with　that　of　pure　ZnO　nanorods　and　pure　Cu2O　nanocubes,　we　were　not　only　able　to　determine　the　electronic　transition　channels,　but　also　resolve　the　charge-transfer　route　and　its　modulation　on　the　transient　excitonic　absorption　and　stimulated　emission　performance.　In　particular,　we　assign　the　broadband　stimulated　emission　with　a　much　reduced　lifetime　as　the　fingerprint　indication,　where　the　lifetime　is　dominantly　limited　by　the　decay　rate　of　the　excitonic　population　on　the　conduction　band　of　Cu2O,　although　multiple　mechanisms　may　have　impact　on　the　corresponding　transition　dynamics.　These　discoveries　not　only　give　deep　insights　into　the　photoelectronics　on　the　Cu2O/ZnO　heterojunctions,　but　also　laid　basis　for　the　design　and　applications　of　these　semiconductors　in　photocatalysis.　©　2025　Elsevier　B.V.