The　inexorable　trend　of　next　generation　spintronics　is　to　develop　smaller,　lighter,　faster,　and　more　energy　efficient　devices.　Ultimately,　spintronics　driven　by　free　energy,　for　example,　solar　power,　is　imperative.　Here,　a　prototype　photovoltaic　spintronic　device　with　an　optical-magneto-electric　tricoupled　photovoltaic/magnetic　thin　film　heterojunction,　where　magnetism　can　be　manipulated　directly　by　sunlight　via　interfacial　effect,　is　proposed.　The　magnetic　anisotropy　is　reduced　evidenced　by　the　out-of-plane　ferromagnetic　resonance　(FMR)　field　change　of　640.26　Oe　under　150　mW　cm−2　illumination　via　in　situ　electron　spin　resonance　(ESR)　method.　The　transient　absorption　analysis　and　the　first-principles　calculation　reveal　that　the　photovoltaic　electrons　doping　in　the　cobalt　film　alter　the　band　filling　of　this　ferromagnetic　film.　The　findings　provide　a　new　path　of　electron　doping　control　magnetism　and　demonstrate　an　optical-magnetic　dual　controllable　logical　switch　with　limited　energy　supply,　which　may　further　transform　the　landscape　of　spintronics　research.　©　2019　The　Authors.　Published　by　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim