In this paper, the effects of the volume fraction of steel fiber. amount of silica fume, and their composite on fatigue perfomance and the mechanism of fatigue damage are investigated. The fatigue equations of steel fiber reinforced concrete and reinforced high-strength concrete are presented. Test results shaw that the effect of volume fraction and length diameter ratio on fatigue performance of concrete is extremely prominent. When silica fume, steel fiber, and their composite are added to high-strength concrete, since the effecss of the two of the nucleation and pozzolanic reaction of silica fume are in the cement marrix, and the effects of steel fiber on the strengthening toughening, and crack arresting in the composite, the interfacial structure of both the fiber cement matrix and aggregate cement matrix is strengthened. The soace superimposing of the effects of the two of the fiber-cement matrix and aggregate-cement matrix appear in the fiber reinforced composite. The double effect af interfacial strengthening and space superimposing of the fiber-cement matrix and aggregate-cement matrix is prodaeed and the inrerfacial structure and character are improved, the process of strengthening. vanishing, and restrengthening of the interface Is caused, and she dimension and the amount of crack sources are reduced. thus delaying crack extension and propagation and the protess of fatigue damage. evidently protonging fatigue life.