Electrochromic smart windows can regulate indoor light through modulating optical transmittance of electrochromic materials to realize energy-saving buildings. Amorphous tungsten oxide (WO₃) film fabricated by magnetron sputtering technology is the most likely to be industrialized due to its advantages of large-area and uniform deposition. However, electrochromic characteristics of the sputtered WO₃ film lag behind those of the solution-process approach due to inefficient ion transport arising from its intrinsically dense atomic structure. In this work, a strategy to develop microstructured magnetron-sputtered WO₃ films by introducing the buried porous electrodes to improve the optical modulation and response time was proposed. The results demonstrate that the porous sputtered WO₃ films prepared by this method exhibit significantly enhanced electrochromic characteristics compared with the dense WO₃ films. When thickness of the porous WO₃ increased to 300 nm, the optimized electrochromic characteristics were achieved, with a remarkable optical modulation of up to 79.08%, coloring and bleaching times of only 2.6 and 2.0 s, and a high coloring efficiency of 52.5 cm²/C. The improved performance is mainly attributed to synergistic effect of the porous indium tin oxide (ITO) electrode and the porous WO₃ film. The porous ITO electrode can increase the surface area with the increased WO₃ component and then increase electronic charges, facilitating the redox reaction process. Moreover, the porous WO₃ film offers a larger surface area for the electrolyte, increases reactive active sites and shortens ion diffusion pathway, which accelerates the ion diffusion and migration process, realizing efficient redox reactions and fast ion transport. This work provides an effective method for preparing high-performance micro- and nano-structured sputtered electrochromic films.