The effects of particle size of activated carbon (AC) on its wettability, electrode coating technology and electric chemical performance were studied to assemble nonaqueous electric double layer capacitors (EDLCs) for high power require-ments. The results show that the specific surface area and total pore volume of AC decrease from 2 137 m2/g to 1 683 m2/g, and 0.95 cm3/g to 0.78 cm3/g, respectively, if it is ball-milled for 8 h. The pore size distributions are similar in the range of 0.7 nm to 3.5 nm for different ball-milling time. There exists oxidation on the surface of AC during the ball-milling process and the ratios of O-C=O oxygen compositions increase whereas those of C-O, C=O decrease. The peeling strength of AC coated on current collector is almost inverse proportion with the particle size of AC as well as the resistance of EDLCs, and its capacitance decreases about 6%.