An　experiment　on　the　test　bench　is　first　carried　out　to　investigate　the　performance　of　a　hydrogen-enriched　engine　at　low　speed,　low　load　and　lean　conditions　in　this　paper.　The　hydrogen　volume　fraction　in　the　intake　is　kept　at　0,　1%,　3%　and　6%　for　a　specified　excess　air　ratio,　respectively.　A　simulation　model　is　built　based　on　AVL　Boost　software.　The　measured　data,　such　as　cylinder　pressure,　intake　air　flow　rate　and　effective　pressure,　are　used　to　validate　and　calibrate　the　model.　Then,　the　performance　of　a　hydrogen-enriched　gasoline　engine　at　a　specified　intake　manifolds　absolute　pressure　with　different　hydrogen　volume　fractions　in　the　intake　and　excess　air　ratios　is　investigated　through　the　model.　Simulation　results　show　that　hydrogen　enrichment　is　effective　in　improving　the　engine　performance　at　low　load,　low　speed　and　lean　conditions.　The　engine　indicates　that　the　thermal　efficiency　and　working　ability　are　improved　with　increasing　hydrogen　addition　fraction　at　lean　condition.　For　a　specified　hydrogen　blending　level,　the　peak　cylinder　pressure　is　reduced　and　the　relevant　crank　angle　for　the　peak　cylinder　pressure　is　retarded　with　the　increase　of　the　excess　air　ratio.　Under　lean　condition,　both　flame　development　and　propagation　periods　are　shortened,　cylinder　pressure　is　enhanced,　and　the　relevant　crank　angle　for　the　peak　cylinder　pressure　is　advanced　after　hydrogen　addition.