the Chinese government. However, the electro catalytic HER suffers from sluggish kinetics, high cost of catalysts and technologies, and instability at certain pH electrolytes due to the scarcity of highperformance earth-abundant catalysts. Although the HER performance of catalysts can optimize by adjusting the acidity of the electrolyte, designing the pseudo-pH-independent electrocatalysts may make the water electrolyzers more affordable and safer for the commercial development of hydrogen energy applications. [2] As a water electrolysis benchmark, precious metal electrocatalyst (Pt) possesses excellent activity overall pH values toward HER, but difficulty in industrialization for its scarcity and high cost. [3][4][5] To date, many nonprecious metal-based HER catalysts with high performance in certain electrolytes have been reported, including transition metal sulfides, [6] selenides, [7][8][9][10][11][12][13][14][15][16][17][18] carbides, [19,20] phosphides, [21,22] and thiopho sphates. [23] However, most developed catalysts deliver attractive HER performance only under acidic conditions, limiting their practical applications. Accordingly, the exploration of pH-universal HER electrocatalysts with competitive Defect engineering of transition metal dichalcogenides (TMDCs) is important for improving electrocatalytic hydrogen evolution reaction (HER) performance. Herein, a facile and scalable atomic-level di-defect strategy over thermodynamically stable VSe 2 nanoflakes, yielding attractive improvements in the electrocatalytic HER performance over a wide electrolyte pH range is reported. The di-defect configuration with controllable spatial relation between single-atom (SA) V defects and single Se vacancy defects effectively triggers the electrocatalytic HER activity of the inert VSe 2 basal plane. When employed as a cathode, this di-defects decorated VSe 2 electrocatalyst requires overpotentials of 67.2, 72.3, and 122.3 mV to reach a HER current density of 10 mA cm −2 under acidic, alkaline, and neutral conditions, respectively, which are superior to most previously reported non-noble metal HER electrocatalysts. Theoretical calculations reveal that the reactive microenvironment consists of two adjacent SA Mo atoms with two surrounding symmetric Se vacancies, yielding optimal water dissociation and hydrogen desorption kinetics. This study provides a scalable strategy for improving the electrocatalytic activity of other TMDCs with inert atoms in the basal plane.