Ru-based　materials　are　promising　electrocatalysts　for　hydrogen　evolution　reaction　(HER)　owing　to　their　low-cost　(one　twenty-fifth　of　Pt)　and　similar　Gibbs　free　energy　of　H*　adsorption　(AGH*)　to　that　of　Pt.　However,　the　inadequate　ability　for　the　water　dissociation　of　Ru　catalysts　is　significantly　impeding　the　water　splitting　efficiency.　In　this　work,　we　demonstrate　an　atomically　ordered　hexagonal　Ru-Ni　alloy　with　compressive-strained　Ru　skin　as　a　high-performance　HER　catalyst　for　significantly　boosting　the　water　dissociation.　The　Ordered　Ru-Ni　achieves　an　optimized　catalytic　activity　for　alkaline　HER　with　a　low　overpotential　of　23　mV　at　10　mA　cm-2,　Tafel　slope　of　25.9　mV　dec-1　and　superior　mass　activity　of　4.83　A　mg-Ru1,　which　is　15.1　times　higher　than　Ru/C.　According　to　DFT　calculations,　the　ordered　RuNi　core　imposes　homogeneous　compressive　strain　on　the　Ru　skin,　resulting　in　an　optimum　binding　energy　towards　H*/OH*　intermediates　on　Ru　active　sites　for　rapid　Tafel　step　kinetics.　Moreover,　the　decreased　H2O　dissociation　energy　barrier　of　Ordered　Ru-Ni　suggests　a　promoted　VolmerTafel　kinetics　is　achieved,　significantly　boosting　the　overall　HER　efficiency.　This　work　provides　a　practical　avenue　for　surface　strain　engineering　of　Ru-based　catalysts　to　promote　the　HER　activity.