Abstract: The influence of six kinds of steel fibers (SF) (short straight, long straight, half ring, triangular, rectangular, circular) with small length-diameter ratio on high-performance concrete was studied. The influence of SF on the fluidity, compressive strength and bending strength of concrete was discussed by changing the volume fraction of SF to change the number and area of the ring formed. The failure mode and mechanism of concrete were analyzed by studying the failure interface. The results show that: the number of closed SF and the area of fiber ring play a major role in the flow of concrete; the circular SF in the closed SF has the best effect on the bending and compressive strength of concrete than other closed SF. In the hybrid test of short straight SF and circular SF, when the volume fraction of circular SF is 1vol% and the volume fraction of short straight SF is 0.5vol%, the improvement on the compressive strength and bending strength of SF reinforced concrete is the best.