Water splitting through electrolysis has been recognized as a promising solution for the production of hydrogen and oxygen to advance many renewable energy conversion and storage systems, while the key is the innovative exploration of cost-efficient electrocatalysts. Herein, interface-modified Ni-Fe-P/Co-P/NF alloys were achieved through a facile electroless plating strategy, in which the constructed interfaces benefited not only from the strong electron interaction but also from the fast mass transfer, significantly boosting the oxygen evolution reaction and hydrogen evolution reaction catalytic performance. More interestingly, water-splitting cells assembled using Ni-Fe-P/Co-P/NF-5L alloys as the cathode and anode, respectively, only requires a cell voltage of similar to 1.52 V at 10 mA cm(-2), far lower than that of the integrated Pt-C/NF and RuO2/NF couple (1.61 V). Also, the Ni-Fe-P/Co-P/NF-5L||Ni-Fe-P/Co-P/NF-5L system shows an outstanding durability over a long-term operation of 48 h at 10 mA cm(-2). The work demonstrates an innovative strategy to construct heterogeneous interfaces for high-performance electrocatalysts and is suggested to be readily extended to regulate heterogeneous interfaces among other binary and ternary electrocatalysts, such as transition metal phosphides/borides, for scaling up water-splitting technology.