Developing non-expensive, highly active and highly stable electrocatalysts for hydrogen evolution has aroused extensive attention, owing to the necessity of novel clean and sustainable energy carriers. In this paper, we report a synthesis of free-standing three-dimensional hierarchical MoS2/CoS2 heterostructure arrays through a convenient process. The investigation of electrocatalytic HER performance suggests that the MoS2/CoS2 hybrid catalyst exhibits significant enhancement in HER(onsetpotential and potential at a current density of 100 mA cm-2 are 20 mV and125 mV, respectively) and superior durability(no shift of current density is observed after a continuous scanning of 3000 times) compared with individual CoS2 and MoS2. The superior HER performance was attributed to the formation of the interface between CoS2 and MoS2 through the electrochemical characterization, Raman, XPS analysis, and the control experiment. The lower onsetpotential, higher current density, excellent durability, and the free-standing structure of the three-dimensional hierarchical MoS2/CoS2 heterostructure array make it a promising cathode catalyst suitable for widespread application.