To　improve　the　idle　economic　performance　of　a　gasoline　engine,　this　paper　experimentally　investigats　the　effects　of　hydrogen　addition　fraction,　cylinder　cutoff,　lean　combustion　and　reducing　idle　speed　on　the　engine　fuel　energy　consumption　at　idle.　The　experiment　was　carried　out　on　a　four-cylinder　gasoline　engine　equipped　with　an　electronically　controlled　hydrogen　port　injection　system.　In　the　experiment,　the　cylinder　closure　was　realized　by　stopping　the　fuel　supply　to　the　specified　cylinders.　Results　show　that　increasing　the　hydrogen　volume　fraction　in　the　intake,　cylinder　cutoff　and　reducing　the　idle　speed　are　all　capable　of　enhancing　the　engine　economic　performance　at　idle.　Among　all　tested　methods,　the　combination　of　hydrogen　addition　and　cylinder　closure　is　the　most　effective　in　decreasing　the　engine　idle　fuel　energy　consumption.　At　a　hydrogen　volume　fraction　in　the　intake　of　6.63%　and　two-cylinder　cutoff　mode,　the　engine　fuel　energy　consumption　is　reduced　by　40.07%,　compared　with　that　of　the　original　engine.　However,　because　of　the　prolonged　combustion　duration,　the　application　of　lean　combustion　is　not　able　to　further　decrease　the　fuel　energy　consumption　of　a　hydrogen-blended　gasoline　engine　at　idle.