To　avoid　the　disadvantages　caused　by　using　silica　fume,　by　using　superfine　cement　(SC)　to　substitute　silica　fume,　a　new　kind　of　ultra　high　performance　concrete　(SC-UHPC)　was　prepared　and　introduced.　The　influence　of　component　types　and　dosages　on　the　mechanical　properties　of　SC-UHPC　was　investigated.　The　results　show　that　40%　ground　granulated　blast　furnace　slag　(GGBFS)　or　10%　fly　ash　(FA)　&　30%　GGBFS　replacing　SC　are　the　most　appropriate　proportions　to　get　high　strength　with　satisfied　workability　and　low　cost.　A　suitable　amount　of　defoaming　agent　(DA)　in　superplasticizer　(SP)　effectively　reduced　the　void　ratio　in　the　UHPC.　To　optimize　the　strength　and　fluidity,　the　rational　natural　sand　distribution　with　lowest　clay　particles　amount　can　be　used.　The　small　sized　steel　fibers　added　into　the　mixture　effectively　improved　the　flexural　behavior　of　SC-UHPC.　Multiple　nonlinear　analysis　show　that,　with　sufficient　calcium　silicate　hydrate　(C-S-H　gel)　and　enough　mixture　fluidity,　the　compressive　strength　of　UHPC　is　closely　related　to　the　water　to　binder　ratio　and　void　ratio,　and　increases　linearly　with　the　incremental　fiber　amount.　Microstructure　analysis　proved　that　the　microstructure　of　SC-UHPC　has　ultra　high　density　and　homogeneity.