Developing low-cost, environmentally friendly and efficient non-precious metal electrocatalysts as alternatives to noble metals for the hydrogen evolution reaction (HER) is highly essential for the sustainable advancement of green hydrogen energy. Herein, a novel heterostructured Ni3P/Ni nanoparticle anchored in nitrogen-doped mesoporous carbon nanofibers (Ni3P/Ni@N-CNFs) is prepared by a facile solid-phase calcination protocol. The results demonstrated that benefiting from the intensive electronic coupling effect at the interface of the Ni3P/Ni heterostructure, the electron configuration of the Ni active site is optimized and thus the favorable HER activity. Furthermore, the N-doped carbon nanofiber scaffold with an extensive mesoporous structure endows Ni3P/Ni@N-CNFs with abundant electrochemically active sites together with excellent conductivity and stability, contributing to fast electron/mass transport. As expected, the resultant Ni3P/Ni@N-CNF electrocatalyst exhibited exceptional HER catalytic properties under universal pH conditions, driving a current density of 10 mA cm-2 at pretty low overpotentials of 121 mV, 145 mV and 187 mV in acidic, basic and neutral solutions, respectively, and retaining the catalytic stability for over 60 h. This intriguing work represents a fresh perspective for designing and exploiting highly advanced phosphide electrocatalysts for green hydrogen fuel production.