Heazlewoodite nickel sulfide (Ni₃S₂) has become attractive for electrocatalytic hydrogen evolution reaction (HER). However, strong sulfur–hydrogen bonds (S–H_ads) formed on the surface of Ni₃S₂ greatly hinder the H_ads desorption and reduce HER activity. Herein, amorphous NiWO₄ nanoparticles-decorated Ni₃S₂ electrocatalysts (NiWO₄/Ni₃S₂) have been constructed via a two-step hydrothermal method. The heterostructures exhibit much better HER performance than original Ni₃S₂ by delivering current densities of −10 and −100 mA cm⁻² at low overpotentials of 136 and 274 mV, while those for Ni₃S₂ are 234 and 424 mV, respectively. Moreover, they display ultra-long stability of 75 h. Theoretical calculation proves the improved activity of NiWO₄/Ni₃S₂ heterostructures is attributed to highly active interfaces between amorphous NiWO₄ nanoparticles and Ni₃S₂ electrocatalysts. The strong electronic interaction between NiWO₄ and Ni₃S₂ decreases the local electron density of Ni and S atoms, facilitates water adsorption on Ni-sites and optimizes hydrogen atom adsorption/desorption on adjacent S-sites with weakened S–H_ads.