A novel hierarchical CoNi2S4 arrays consisting of uniformly coverage of thin sheets and numerous nanobranches on Ni foam has been successfully prepared via a simple one-step hydrothermal route without any surfactant and template. The CoNi2S4 arrays were investigated as electrode material for supercapacitors. The ordered CoNi2S4 arrays self-grown on Ni foam provided an excellent conducting connection with electrode substrates. Meanwhile, the thin sheets on top of the arrays is interconnected, forming a highly specific surface area. The unique architecture has constructed many independent nanospaces to participate in electrochemical reaction. Detailed electrochemical characterization showed the novel structure has an excellent electrochemical capacitance, high rate performance and high areal capacitance. The cost-effective synthesis of CoNi2S4 arrays and remarkable electrochemical performance provided great potential for this type of hybrid hierarchical nanostructures in supercapacitors.