Abstract: Electrochromic film was fabricated with a tungstic oxide target by the RF reactive magnetron process.Orthogonal test method was used to optimize process parameters and then to design excellent performance Electrochromic film.Heat treatment process was adopted to improve the endurance of electrochromic performance.Results showed that Electrochromic properties improved Significant.Variation of the transmittance（ΔT） can reach 89.3% in the preparation condition of w（O）=60%,p=2.5Pa and P=145w.Coloring rate increased slightly while,duration of Electrochromic state and ion storage capacity can extend to 32 h and 3.96 mC/cm²,respectively;simultaneously,cycling stability,crystallization,density and electrochromic response time were ameliorated under justifiable heat treatment process.