The effect of deashing approache on pore size distribution and electrochemical performance of potassium humate based activated carbons was investigated.The as-prepared activated carbons that were deashed before or after carbonization of potassium humate at 700 ℃for 1 h under N2 atmosphere are denoted as AC1,AC2,respectively.As a comparison,the AC3 was prepared from commercial potassium humate without deashing treatment.The pore structure and morphology of as-prepared activated carbons were characterized by low temperature N2 adsorption and scanning electron microscope.The capacitive behaviors were further stud-ied by galvanostatic charge/discharge,cyclic voltammetry,leakage current and electrochemical impedance spectroscopy.It was found that deashing before carbonization can create the micropores in the range of 0-1.2 nm,while deashing after carbonization ex-hibits the use of template and be more helpful to the formation of mesopores(2.0-10.2 nm).Meanwhile,the AC1 based electrodes exhibit specific capacitance with value of 164 F/g at a current density of 50 mA·g-1,excellent cycling stabilities,lower interfacial electron transfer resistance and lower leakage current value(13.5 μA).