Biosensors　based　on　terahertz　(THz)　metasurfaces　have　recently　attracted　widespread　attention.　However,　few　have　been　reported　so　far　because　it　is　a　challenge　to　achieve　ultrasensitive　multidimensional　detection　in　the　THz　spectrum.　Here,　we　propose　a　novel　THz　biosensor　that　consists　of　a　metasurfaces　and　a　metal　oxide　semiconductor-like　structure　(MOSLS),　which　is　based　on　patterned　graphene-polyimide-perovskite.　We　varied　the　photoconductivity　of　the　MOSLS　via　the　electrostatic　doping　effect.　The　biosensor　could　detect　whey　protein　down　to　a　concentration　limit　of　6.25　ng/mL.　Significant　responses　in　frequency,　phase,　and　transmission　amplitude　were　all　detected　for　different　protein　concentrations.　The　transmission　value　difference,　frequency　shift,　and　phase　difference　increased　with　the　concentration　of　whey　protein,　clearly　demonstrating　multidimensional　biosensing.　Moreover,　by　applying　lasers　with　different　wavelengths,　we　have　realized　reversible　biosensing　in　THz　region　for　the　first　time.　These　results　are　very　promising　for　applications　of　THz　metasurfaces　in　the　field　of　biosensing.