Electronic textiles promise to provide an intelligent platform to enlarge the scope of wearable electronic applications. Therefore, the combination of flexible energy storage devies into wearable systems is a key for operating these electronic textiles during bending, knotting, and rolling. Nonetheless, the application of fibrous supercapacitors consisting of a gel-electrolyte and carbon fiber electrode is still obstructed by low capacitance, low rate-performance, and poor cycling stability owing to the inefficient interface between the gel-electrolyte and electrode. Here, a fibrous supercapacitor is obtained using an optimized gelelectrolyte that improves the ionic diffusion capability. The optimized fibrous supercapacitor shows a superior electrochemical performance, including high specific capacitance of 41 mF cm.2 at current density of 2.0 μA cm.2, high-rate performance with 17 mF cm.2 at a current density of 15.0 μA cm.2, and outstanding cycling stability (88% after 3,000 cycles at a current density of 200.0 μA cm.2). The excellent energy storage performance is mainly attributed to the optimzied interface between the gelelectrolyte and electrode material, leading to an improved ionic diffusion capability.