Due to the problems of large amount of cementitious material and high cost of Ultra High Performance Concrete (UHPC), the UHPC system was mixed with coarse aggregate and river sand instead of quartz sand, and the preparation of UHPC with coarse aggregate is successful resulting in excellent mechanical properties. Meanwhile, the effects of the coarse aggregate content and geometric parameters of the steel fiber on the mechanical properties of the UHPC with coarse aggregate were studied. The results showed that, with the increase of coarse aggregate content (0~800 kg/m3), the compressive strength of UHPC increased firstly and then decreased, the elastic modulus increased almost linearly. When the content of coarse aggregate was in 0~400 kg/m3, the flexural strength and initial crack strength of UHPC changed little, while when the content of coarse aggregate was 400~800 kg/m3, the flexural strength and initial crack strength of UHPC decreased obviously. With the increase of the content of coarse aggregate (0~800 kg/m3), the flexural load-deflection curve of UHPC was obviously changed, and the flexural toughness decreased obviously, but a strain- hardening process was observed. With the increase of the length of steel fiber, the compressive strength, flexural strength and flexural toughness of UHPC increased, but the static compression modulus and initial crack strength of UHPC changed little.