To further improve the electrochemical performance of MXene materials, MXene(Ti3C2Tx)/α-Fe2O3 nanocomposites are fabricated by a self-assembly method via electrostatic attraction between negatively charged Ti3C2Tx MXenesand positively charged cocoa-like α-Fe2O3 nanoparticles at room temperature. As a negative electrode material, the resulting nanocomposites show excellent electrochemical performance, including a wide operating potential of 1.2 V (−1.2–0 V), a high specific capacitance of 405.4 F g−1 at the current density of 2 A g−1 and a specific capacitance of 197.6 F g−1 even at the current density of 20 A g−1 in 5 M LiCl. In addition, the nanocomposites possess a high cycling stability with 97.7% capacitance retention of the initial capacitance after 2000 cycles. The impressive results indicate that the prepared MXene(Ti3C2Tx)/α-Fe2O3 nanocomposites is a promising negative electrode material for supercapacitor. The self-assemble of MXenes and metal oxides will provide more opportunities for their application in energy storage.