DME　and　hydrogen　were　blended　with　air　in　intake　and　the　HCCI　combustion　was　realized.　The　speed　of　engine　was　hold　at　1400　r/min　and　the　mass　flow　rate　of　DME　was　ranged　at　2.6　and　3.5　L/min.　With　the　hydrogen　fraction　increasing,　the　excessive　air　coefficient　λ　was　reduced　until　the　engine　knocked.　The　result　showed　that　DME　blended　with　hydrogen　could　increase　the　peak　pressure,　heat　release　rate　and　BMEP.　The　peak　pressure　was　improved　26.4%　when　the　DME　flow　was　3.5　L/min.　In　the　emissions,　CO　and　HC　could　be　reduced,　and　CO　emission　was　only　20%~30%　of　the　original　data　after　hydrogen　enriched.　However,　NOx　emissions　increased　with　the　addition　of　hydrogen.