A cost effective hydrogen evolution reaction (HER) catalyst that does not use precious metallic elements is a crucial demand for environment-benign energy production. The family of earth-abundant transition metal compounds of nitrides, carbides, chalcogenides, and phosphides is one of the promising candidates for such a purpose, particularly in acidic conditions. However, its catalytic performance is still needed to be enhanced through novel material designs and crystalline engineering. Herein, a chemically and electronically coupled transition metal phosphosulfide/N-doped carbon nanotubes (NCNT) hybrid electrocatalyst is fabricated via a two-step synthesis. The uniquely designed synthesis leads to the material morphology featuring a core-shell structure, in which the crystalline metal phosphide core is surrounded by an amorphous phosphosulfide nanoshell. Notably, due to the favorable modification of chemical composition and surface properties, core-shell CoP@PS/NCNT exhibits the noticeable HER activity of approximately -80 mV @ -10 mA cm(-2) with excellent durability, which is one of the highest active nonnoble metal electrocatalysts ever reported thus far.