One-dimensional(1D, wire-and fiber-shaped)supercapacitors have recently attracted interest due to their roll-up, micrometer size and potential applications in portable or wearable electronics. Herein, a 1D wireshaped electrode was developed based on Fe_3O_4 nanosheet arrays connected on the Fe wire, which was prepared via oxidation of Fe wire in 0.1 M KCl solution(pH 3) with O2-rich environment under 70 °C. The obtained Fe_3O_4 nanosheet arrays displayed a high specific capacitance(20.8 m F cm~(-1) at 10 mV s~(-1)) and long cycling lifespan(91.7% retention after 2500 cycles). Theexcellent performance may attribute to the connected nanosheet structure with abundant open spaces and the intimate contact between the Fe_3O_4 and iron substrate. In addition, a wire-shaped asymmetric supercapacitor was fabricated and had excellent capacitive properties with a high energy density(9 l Wh cm~(-2)) at power density of 532.7 l W cm~(-2) and remarkable long-term cycling performance(99% capacitance retention after 2000 cycles).Considering low cost and earth-abundant electrode material, as well as outstanding electrochemical properties, the assembled supercapacitor will possess enormous potential for practical applications in portable electronic device. One-dimensional (1D, wire-and-fiber-shaped) supercapacitors have interest in attracting to their roll-up, micrometer size and potential applications in portable or wearable electronics. Herein, a 1D wireshaped electrode was developed based on Fe_3O_4 nanosheet arrays connected on the Fe wire, which was prepared via oxidation of Fe wire in 0.1 M KCl solution (pH 3) with O2-rich environment at 70 ° C. The obtained Fe_3O_4 nanosheet arrays showed a high specific capacitance (20.8 m F cm ~ (- 1) at 10 mV s ~ (-1)) and long cycling lifespan (91.7% retention after 2500 cycles). The excellent performance may attribute to the connected nanosheet structure with abundant open spaces and the intimate contact between the Fe_3O_4 and iron substrates. In addition, a wire-shaped asymmetric supercapacitor was fabricated and had excellent capacitive properties with a high energy density (9 l Wh cm -2) at power density of 532.7 l W cm -2 and remarkable long-term cycling performance (99% capacitance retention after 2000 cycles) .Considering low cost and earth-abundant electrode material, as well as outstanding electrochemical properties, the assembled supercapacitor will possess enormous potential for practical applications in portable electronic device.