Abstract: To investigate the effects of silica fume on the mechanical properties of Reactive Powder Concrete( RPC) ， the compression strength，split tensile strength and flexural tensile strength of RPC with five different silica fume volumetric contents were researched by the compressive，split tensile and flexural tensile tests of RPC cubic and beam specimens． It was shown that the increasing content of silica fume could improve the mechanical properties of RPC effectively，but there existed an optimum content of silica． In order to meet the requirements of the high performance， good workability and economy simultaneously，the volumetric content of silica fume being 12% could obtain the good performance RPC200． In addition，the relationships between the measured strengths and the volumetric contents of silica fume were empirically formulated．