Direct preparation of activated carbon (AC) from coal was reported by microwave heating with potassium hydroxide as activation agent. Electrochemical properties of AC electrodes were investigated by cyclic voltammetry, constant current charge–discharge. The results show that functional groups on AC include –C=O, –O–H and –C–O. The micropore volume of AC from different coal totals 48.5–95.6%. The total pore volume of AC from different coal passes through a maximum with the decrease of volatile mater content in coal. The specific surface area and total pore volume of AC from Qing ting coal reach 1874 m2 g-1 and 1.00 cm3 g-1, respectively. The specific capacitance and energy density of AC from higher coal rank is usually bigger than that of AC from lower coal rank.