A　large　size　Split　Hopkinson　Pressure　Bar　(SHPB)　of　75　mm　was　used　to　study　the　dynamic　mechanical　behavior　of　fiber　reinforced　high　strength　concrete　under　an　impact　loading.　The　impact　compression　experiments　with　three　different　strain　rate　ranges　were　conducted　for　steel　fiber　reinforced　high　strength　concrete　specimens　and　polyvinyl　alcohol　fiber　(PVA)　reinforced　high　strength　concrete　specimens　with　three　fiber　contents.　The　results　show　that　at　high　strain　rate,　the　dynamic　stress-strain　relationships　are　strain　rate　dependent.　It　means　that　the　fiber　reinforced　high　strength　concrete　is　sensitive　to　the　strain　rate.　The　failure　stress　and　failure　strain　increase　with　increasing　the　strain　rate.　The　energy　absorbing　capability　of　the　steel　fiber　and　PVA　fiber　in　concrete　is　exhibited　in　the　process　of　the　material　failure　only　after　the　peak　stress　is　reached.　The　mechanism　of　the　toughness　increasing　effect　and　energy　absorbing　of　fiber　reinforced　high　strength　concrete　is　also　analyzed　and　discussed.