Abstract: The polymer solid state electrochromic device was fabricated by using the composite film of ethylene-vinyl alcohol copolymer（EVOH）/polypyrrole（PPy） and polyether-based urethane /lithium perchlorate（LiClO₄） electrolyte.The color of the obtained device changes reversibly from yellow to brown（blue） when an applied voltage varies among-1.0,-1.5,-2.0,-2.5V and 1.0,1.5,2.0,2.5V.The UV/VIS spectral change,the response time of doping/ undoping processes for the electrochromic device,and the effect electrolyte of concentraton on the processes were studied.The results indicate that the electrochromic device has a short response time and a big difference of transmittance at 800 nm.