Hierarchical　microporous　and　mesoporous　biocarbons　derived　from　kapok　fruit　peels　were　prepared　by　a　two-step　method.　First,　a　carbon　precursor　was　prepared　from　the　kapok　fruit　peels　by　precarbonization　at　lower　temperature,　and　then　it　was　activated　at　a　higher　temperature　with　KOH　as　an　activation　agent.　Micropores　and　mesopores　of　the　biocarbons　were　controlled　by　adjusting　the　mass　ratio　of　KOH　to　the　carbon　precursor.　Especially,　the　biocarbon　AC　4　that　was　prepared　with　a　KOH/carbon　precursor　mass　ratio　of　4:1　possesses　a　sheet　structure　with　hierarchical　pores,　a　high　specific　surface　area　of　1257.6　m　2　/g,　and　a　pore　volume　of　1.05　cm　3　/g.　The　AC　4　biocarbon　exhibits　a　maximum　specific　capacitance　of　332.3　F/g　at　a　current　density　of　1　A/g,　and　it　still　remains　a　specific　capacitance　as　high　as　180　F/g　with　increasing　the　current　density　up　to　50　A/g.　The　AC　4　electrode　material　also　possesses　an　excellent　life　span　after　10　000　cycles.　On　the　basis　of　these　obtained　results,　the　relationship　between　the　electrochemical　performance　and　the　structure　of　the　biocarbon　was　discussed.　©　Copyright　©　2019　American　Chemical　Society.