Biochar　is　widely　employed　as　an　electrode　of　supercapacitor.　In　this　work,　one-step　pyrolysis　and　chemical　activation　method　were　introduced　to　prepare　porous　biochars　from　tea　saponin　(TS).　The　performance　differences　of　biochars　prepared　by　two　methods　were　studied.　On　this　basis,　further　researches　were　carried　out　to　explore　the　influence　of　the　mass　ratio　of　KOH/pre-carbonized　precursor　on　the　structure　and　electrochemical　performance　of　the　biochars.　All　samples　were　characterized　by　scanning　electron　microscope　(SEM),　transmission　electron　microscope　(TEM),　Brunauer-Emmett-Teller　(BET),　X-ray　diffraction　(XRD),　Raman　spectra,　Fourier　transform　infrared　spectroscopy　(FT-IR)　and　X-ray　photoelectron　spectroscopy　(XPS).　The　results　revealed　that　KOH　could　effectively　increase　the　specific　surface　area　of　biochar.　The　specific　area　of　AC(TS)-1.0　prepared　with　a　KOH/pre-carbonized　precursor　mass　ratio　of　1:1,　is　up　to　1550.03　cm(2)/g　with　a　pore　volume　of　0.9076　cm(3)/g,　and　the　structure　was　highly　amorphous　and　disordered.　The　FT-IR　and　XPS　results　showed　that　there　are　various　functional　groups　on　the　AC(TS)-1.0　biochar　surface.　These　structural　and　compositional　advantages　lead　to　a　higher　specific　capacitance　(278　F/g)　of　AC(TS)-1.0　in　an　aqueous　electrolyte　and　a　high　energy　density　of　27.01　Wh/kg　at　an　organic　electrolyte.　Meanwhile,　the　as-prepared　AC(TS)-1.0　has　excellent　cycling　stability　over　10,000　cycles　in　various　electrolytes.