High performance flexible asymmetric supercapacitors based on carbon cloth are continuously prepared by a quick, low-cost, simple and scalable one-step electrochemical process within minutes without any other additives. The Fe2O3 is electrochemically deposition carbon cloth for the negative electrode, while the PEDOT and MnO2 are electrochemically co-deposited on carbon cloth for positive electrode. All processes take place within 1 min, therefore, this method can be applied in a continuous preparation mode for large-scale production, which implies its application potential in the industry. This is the first report of one-step continuous prepare of the flexible electrodes for supercapacitor. In addition, as assembled supercapacitors consisting of Fe2O3@carbon cloth and MnO2-PEDOT@carbon cloth, it achieves a high operating voltage of 2 V and a high energy density of 340 μW h cm−3 at a power density of 1.212 × 105 μW cm−3. This supercapacitor also possesses excellent flexibility and stability with 95% capacitance retained even after 1000 times bending. The larger-sized supercapacitor is further tested as watchband to power an electronic watch or light 41 LEDs for minutes. The low-cost continuous preparation method with high performance endows the flexible carbon cloth various promising applications, such as flexible asymmetric supercapacitors, flexible battery, catalysts and surface treatment.