Tests　were　carried　out　on　the　properties　of　Ultra-High　Performance　Concrete　(UHPC)　by　partially　or　completely　replacing　Silica　Fume　(SF)　by　Low-temperature　Rice　Husk　Ash　(L-RHA).The　results　show　that　the　activity　and　adsorptive　capacity　of　L-RHA　is　greater　than　SF;　The　compressive　strength　of　UHPC　is　increased　by　both　the　filling　effect　and　the　secondary　hydration　effect　for　L-RHA,　but　only　by　the　filling　effect　for　SF.　However,　more　than　10%　dosage　of　L-RHA　or　SF　reduces　the　early　compressive　strength　of　UHPC.　The　compressive　strength　of　UHPC　with　two　blends　of　L-RHA　and　SF　with　less　than　10%　dosage　of　each　ingredient　is　higher　than　the　one　with　only　a　blend　of　ingredient,　L-RHA　or　SF.　©　(2013)　Trans　Tech　Publications,　Switzerland.