Using high strength wire (HSW) as a longitudinal reinforcement in UHPC can make full use of the outstanding properties of UHPC. In this paper, the flexural test was carried out on normal rebar-reinforced UHPC (NRRU) and HSW reinforced UHPC (HSWRU) slabs. The cracking resistance, failure modes, bearing capacity and deformation characteristics of specimens were investigated. The test results indicated that both HSWRU and NRRU specimens exhibited excellent flexural performance under concentrated loads. Fewer inclined cracks and a slower cracking development process were observed for HSWRU specimens, and brittle failure did not occur during the whole loading process. As compared to HSWRU specimens, the cracking and ultimate load of NRRU specimens increased by 24.64% and 85.47%, respectively, due to a higher reinforcement ratio. Then the theoretical method available for flexural capacity and ductility calculation was proposed, and the feasibility was substantiated through test results. In addition, the traditional deformation ductility coefficient was found to be 30% conservative against the applied energy ductility coefficient. Finally, the extensive parametric analysis revealed that the increase of the reinforcement ratio and the strength of the steel rebar significantly enhanced the ultimate capacity, while the ductility coefficient was obviously weakened. Inversely, those two factors had little impact on the cracking capacity. Moreover, section height was found to be beneficial for both the flexural capacity and ductility of specimens.