Developing highly-efficient hydrogen evolution reaction (HER) electrocatalysts made from non-precious metal is quite essential to the renewable energy research. We, here, report CoP nanoparticles with the diameter of 5-12 nm encapsulated in 3D N-doped porous carbon (CoP@3D-NPC) material, which was synthesized via a simple, efficient and easily large scale synthesis approach using thermal treatment of cobalt nitrate-encapsulated within the 3D N-doped porous graphitic carbon nanosheet derived from inexpensive materials (PVP-30) and followed by a phosphorization treatment. The unique 3D porous carbon structure cannot only provide multidimensional electron/ion transmission path to reduce the diffusion distance, but also prevent encapsulated CoP nanoparticles from directly contacting with electrolyte to ensure the interface stability. Evidenced by electrochemical testing, the synthesized material CoP@3D-NPC can operate well under acidic, neutral or alkaline condition for hydrogen evolution reaction.