In this work, water dispersed electrochromic polymer nanoparticles (WDENs) prepared with miniemulsion process are introduced into electrochromic polymer (ECP) electrode for the first time. The poly [2, 3-bis-(3-octyloxyphenyl) quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl]) nanoparticle (NP) electrode shows much faster switching speed than the compacted electrode (e.g. 2.10 s vs. 24.15 s for coloring, 8.65 s vs. 25.95 s for bleaching @ 0.4 V; 1.30 s vs. 9.20 s coloring and 1.7 s vs. 2.90 s for bleaching @ 1.0 V). Moreover, the potentiality of WDENs for universal ECPs is demonstrated. The microelectrochemical measurement indicates much more efficient counter-ion diffusion between the electrolyte and the NP films than the compacted films, which results in much faster electrochromic switching. Besides the facile and eco-friendly processing of the WDENs, all solution and low cost fabrication of ECP NP films suggest their broad applications in commercial production of polymer electrochromic display and great potential for other polymer electrochemical electronics.