The WO3/PANI core/shell nanowire array is prepared by the combination of solvothermal and electropolymerization methods. The core/shell nanowire array film shows remarkable enhancement of the electrochromic properties. In particular, a significant optical modulation (59% at 700nm), fast switching speed, high coloration efficiency (86.3cm2C−1 at 700nm) and excellent cycling stability are achieved for the core/shell nanowire array film. The improved electrochromic properties are mainly attributed to the formation of the donor–acceptor system, and the porous space among the nanowires, which can make fast ion diffusion and provide larger surface area for charge-transfer reactions. The data indicate great promise for the WO3/PANI core/shell nanowire array as a potential multicolor electrochromic material.