Abstract: In order to take activated carbon,carbonized paulownia leaves and orange peel as the fuel of direct carbon fuel cell,their physicochemical and electrochemical properties were investigated.The carbon type in fuel was characterized by <i<X</i<-ray diffraction method.And the energy dispersive spectrometer and Raman patterns were used to analyze the element content of fuel.The specific surface area and pore structure of the fuels were tested by BET.The results show that carbonized orange peel fuel contains potassium and high content of amorphous carbon,which is beneficial to the Boudouard reaction and electrochemical reaction of carbon.The carbonized orange peel possesses a specific surface area of 74 m<sup<2</sup<· g<sup<-1</sup<,a small porosity and a large bulk density,which indicate the large contact interface between the anode and fuel.When the carbonized orange peel is used as a fuel,the maximum power density of a fuel cell can reach up to 572.6 m W· cm<sup<-2</sup< at 800 ℃.Obtaining from carbonization of non-woody orange peels with high water content,the biomass carbon can provide excellent performance for the fuel of direct carbon fuel cell.