In order to improve the static mechanical properties and impact resistance of cement-based materials and to reduce the amount of cement for the purpose of less greenhouse gas emissions,mineral admixtures of silica fume(10%,wt.),steel fiber(2%,by volume) for functional components,matched with high efficiency water reducing agent(1.5%~2.0%,wt.) were used to prepare high-toughness cement composites in this study.The quasi-static and dynamic mechanical properties and microstructure evolution of the high toughness cement-based composites were investigated by the quasi-static compressive/flexural strength test,split hopkinson pressure bar test(SHPB),isothermal calorimeter and thermal gravimetric analyzer.The results showed that the typical failure process of cement-based composites under impact loading(impact rate of 0.5 MP/s) can be divided into three stages.Only limited amount of spalling or flying phenomenon of pastes occurred in high-toughness cement-based composite,while the control cement-based materials were significantly damaged until the whole samples were broken.The quasi-static mechanical properties(compressive strength and flexural strength reached 61.4 MPa and 23.9 MPa at 1 d) and dynamic compressive strength(to 123.3 MPa at 28 d) of cement-based composites were both improved with 10% silica fume addition.According to the microstructure evolution results,under the combined action of silica powder and water reducing agent,the main peak of heat release rate of slurry hydration was advanced,and the content of calcium hydroxide in the main hydration product phase was reduced,which reduced the orientation of calcium hydroxide distribution in slurry and helped to improve the microstructure of slurry.