In order to study the influence of steel fiber characteristics and specimen forming method on the bending properties of ultra-high performance concrete (UHPC), a four-point bending test is carried out, and the design parameters are steel fiber length-diameter ratio, volume fraction, shape and specimen forming method. The results show that: 1) The length-diameter ratio of steel fiber is increased from 37 to 65, the peak toughness ratio of UHPC is increased by 52.47%, and the post-peak toughness is decreased first and then increased; 2) The initial crack load, peak load and bending toughness of UHPC all are increased with the increase of steel fiber content; 3) Compared with UHPC by stirring method, the peak toughness of UHPC molded by slurry method is decreased by 24.32%~35.78%; 4) Compared with the end hook steel fiber reinforced UHPC, the peak load and bending toughness of the arc steel fiber reinforced UHPC are decreased; 5) The flexural toughness of UHPC in flexural hardening and softening sections can be evaluated from the perspective of energy ratio and strength ratio. The results can provide some references for the wide application of UHPC.