We successfully fabricate flexible electrochromic supercapacitor (SC) electrodes employing novel flexible transparent conducting substrates. The as-synthesized flexible electrochromic SC electrodes exhibit great electrochemical performances (13.6 mF cm⁻², 138.2 F g⁻¹) and high coloration efficiency (80.2 cm² C⁻¹), which demonstrate their potential applications in flexible smart windows combining energy storage and electrochromism.