In order to increase the replacing amount of waste rubber within concrete and to ensure its mechanical strength meet the designed standard, the paper investigated the effects of silica fume content and waste rubber content on the 28 d compressive strength, flexural strength and splitting tensile strength of concrete. The morphology of concrete was explained by using scanning electron microscopy (SEM), and the failure process was simulated by using ABAQUS finite element software at the microscopic level. The results show that the adding of waste rubber reduces the mechanical properties of concrete. The higher the waste rubber content is, the lower the mechanical properties is. Silica fume can improve the mechanical properties of rubber concrete, and the optimal content is 7% (mass fraction). The mechanical properties of concrete hybrid incorporating of 7% silica fume and 15% (volume fraction) rubber are consistent with the control one, and 28 d compressive strength, flexural strength and splitting tensile strength are 50.3, 3.56, and 2.64 MPa, respectively, meeting the designed requirements of C40 concrete, which are 24.2%, 13.4%, and 10.0% than those of concrete single doped with 15% rubber concrete. There are a lot of defects on the interface between rubber and cement mortar, and the higher the waste rubber is, the more the microscopic defects is. The adding of waste rubber leads to the micro-cracks transfer from the coarse aggregates interface to rubber particles, and the higher the rubber content is, the more the micro-cracks is. The incorporating of silica fume is effective in reducing the rubber particle interface cracks, and improve concrete strength.