A high elastic modulus concrete was designed on the base of modified Furnas model and close-packing aggregates test results. In addition, steel microfibers were used to improve the toughness of high elastic modulus concrete. The effect of steel microfiber on fluidity, strength, elastic modulus and bending toughness of concrete under close-packing aggregates state was investigated. The results show that using close-packing aggregates and proper steel microfiber, the static and dynamic elastic modulus of concrete are up to 50.15 GPa and 53.23 GPa, respectively, the fracture energy is about 5 680.45 N/m, and the residual bending toughness ratio increases from 0 to 0.43. Moreover, with the increase of steel microfiber content, the fluidity of high elastic modulus concrete decreases, while the flexural strength, elastic modulus and bending toughness increase. With the increase of steel microfiber content, the compressive strength increases first and then decreases. In close-packing aggregates state, considering fluidity, mechanical properties and engineering economy, the resonable amount of steel microfiber in high elastic modulus concrete is 0.4% (volume fraction).