Searching for high-efficiency nonprecious bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is paramount for the advancement of water electrolysis technologies and the associated renewable energy devices. Modulation of electronic structure of an electrocatalyst via heterointerface engineering represents an efficient strategy to improve its electrocatalytic performance. Herein, a feasible hydrothermal synthesis of a novel heterostructured catalyst was demonstrated, comprising CoS2 nanocubes and vertically aligned MoS2 nanosheet arrays directly grown on flexible and conductive carbon cloth (CC) substrate (denoted as CoS2/[email protected]). Thanks to the elaborate interface engineering and vertically aligned nanosheet arrayed architecture, the resultant self-supported CoS2/[email protected] electrode possessed enriched exposed active sites, modulated electronic configuration, multidimensional mass transport channels, and outstanding mechanical strength, thereby affording exceptional electrocatalytic performances towards the HER and OER in alkaline electrolyte with overpotentials of 71 and 274 mV at 10 mA cm(-2), respectively. In addition, a two-electrode electrolyzer assembled by CoS2/[email protected] required a cell voltage of 1.59 V at 10 mA cm(-2) with nearly 100 % faradaic efficiency and remarkable durability, showing great potential for scalable and economical water electrolysis.