An　experimental　study　was　conducted　on　a　direct-injection　spark-ignition　(DISI)　engine　fuelled　with　hydrogen-natural　gas　blends　with　the　introduction　of　EGR　(exhaust　gas　recirculation).　The　effects　of　the　EGR　rate,　the　hydrogen　fraction　and　the　injection　timing　on　the　engine　performance　and　emission　characteristics　were　investigated.　The　results　show　that　the　hydrogen　addition　reduced　the　brake　mean　effective　pressure　(BMEP)　and　the　brake　thermal　efficiency　at　the　lower　EGR　rate　but　increased　the　BMEP　and　the　brake　thermal　efficiency　at　the　higher　EGR　rate.　The　BMEP　decreased　with　an　increase　in　the　EGR　rate,　and　the　brake　thermal　efficiency　increased　at　first　and　then　decreased　with　an　increase　in　the　EGR　rate.　The　NOxconcentration　decreased　with　an　increase　in　the　EGR　rate　and　increased　with　the　hydrogen　fraction.　The　HC　emission　increased　with　the　EGR　rate　and　decreased　with　an　increase　in　the　hydrogen　fraction.　The　CO　emission　changed　slightly　with　the　EGR　rate　and　decreased　with　an　increase　in　the　hydrogen　fraction.　In　addition,　the　variation　coefficient　of　indicated　mean　effective　pressure　Cimepincreased　with　the　EGR　rate,　and　the　hydrogen　addition　could　reduce　the　Cimepmore　effectively　for　late　injection.