An activated carbon (AC) with high-porosity was prepared from Zizania latifolia leaves by a one-step method combining chemical and physical activation. K2CO3 was employed as a chemical reagent, and air as a physical agent. During the activation, several key parameters were discussed, including the effects of activation temperature, K2CO3 impregnation ratio, amount of introduced air on the surface area and pore volumes evolution of the ACs derived from the Zizania latifolia leaves. The synergistic effect between the chemical agent and the physical agent was also investigated. Under optimal activation conditions, the as-synthesized AC attained a maximum surface area up to 2481 m(2)/g, with 1.21 cm(3)/g pore volume, and it had a micro/meso porosity developed by the combining activation. The crystal sizes of the as-synthesized AC along the a- and c-axes were about 5 nm and 1-2 nm, respectively. The average thickness of the crystallites is 3-4 layers with about 0.37 nm interlayer spacing.