Construction of self-supported porous metal sulfide arrays is critical for the development of high-performance electrochemical energy storage devices. Herein we report hierarchical porous Co/FeS2–C core/branch nanowires arrays by the combination of facile solution-based methods. FeS2–C nanoflakes branch is uniformly coated on the Co nanowire core forming composite core/branch arrays. The as-prepared Co/FeS2–C core/branch nanowire arrays possess combined properties of highly porous structure and strong mechanical stability. As cathode of lithium ion batteries, the Co/FeS2–C core/branch nanowire arrays exhibit good electrochemical performances with initial discharge capacity of 850 mAh g−1 at 0.25 °C and stable high-rate cycling life (539 mAh g−1 after 70 cycles at 0.25 °C). The hierarchical core/branch architecture provides positive roles in the enhancement of electrochemical properties, including fast transportation path of electron, short diffusion of ions and high contact area between the active material and electrolyte.