This　paper　analyzes　the　main　sources　of　exergy　destruction　during　the　non-equilibrium　combustion　of　the　hydrogen-natural　gas　engine.　The　performance　of　five　representative　CH4/H2　kinetic　models　in　the　literature　is　re-evaluated　and　a　method　for　calculating　exergy　destruction　of　elementary　reactions　is　preliminarily　established　based　on　non-equilibrium　thermodynamics.　Combined　with　the　selected　kinetic　model,　the　exergy　destruction　behaviors　during　the　auto-ignition　of　CH4/H2　mixtures　under　different　initial　conditions　(temperatures,　equivalence　ratios,　hydrogen　ratios)　are　numerically　analyzed.　According　to　the　results,　with　the　initial　temperature　increases,　exergy　destruction　caused　by　chemical　reaction　decreases,　while　exergy　destruction　from　incomplete　combustion　increases.　Moreover,　H2　addition　shows　little　effect　on　the　total　exergy　destruction,　but　effectively　extends　the　low　exergy　destruction　zone　of　CH4　combustion.　The　time　histories　of　exergy　destruction　at　different　temperatures　and　varied　H2　additions　are　compared;　the　rates　of　production　(ROP)　of　HO2　and　OH　radicals,　as　well　as　the　contribution　of　the　elementary　reactions　that　dominate　their　generation　and　consumption　to　the　exergy　destruction,　are　analyzed,　to　reveal　the　effects　of　initial　temperature　and　H2　addition　on　exergy　destruction　of　CH4　combustion.　Furthermore,　the　discrepancy　in　exergy　destruction　between　CH4　high-/low-temperature　oxidation　pathways　is　thermodynamically　clarified　by　comparing　the　Gibbs　free　energy　of　key　species　during　fuel　oxidation.　The　research　results　reveal　the　effects　of　H2　addition　on　exergy　destruction　during　CH4　combustion　at　molecular　reaction　level,　and　is　expected　to　provide　theoretical　guidance　for　further　reducing　exergy　destruction　of　hydrogen-natural　gas　engine　combustion.　©　2022　Xi＇an　Jiaotong　University.　All　rights　reserved.