To study the influence of fiber distribution on the mechanical properties of Reactive Power Concrete(RPC) members under quasi-static loading, the four-point bending test was carried out on aligned steel fiber RPC and steel fiber RPC specimens at the same fiber content (2%) and different fiber lengths (13~20 mm).By selecting the initial crack point, peak point and other characteristic points on the bending load-deflection curves, the bending properties of aligned steel fiber RPC(ASFRPC) and steel fiber RPC(SFRPC) were analyzed quantitatively. The experimental results show that orientation coefficient of steel fibers in the direction of main tensile stress has a strong impact on the deflection hardening behavior in bending. First of all, the bending tensile peak stress and bending ductility of ASFRPC is greater than that of SFRPC.In particular, when the mid-span deflection reaches L/150, the residual strength of ASFRPC specimen is still 4.35~6.9 MPa higher than that of the initial crack strength.Secondly, when the fiber length increases from 13 mm to 20 mm, the flexural property of ASFRPC specimen improves more significantly than that of SFRPC specimen, and the advantage of fiber length diameter ratio is more significant with the increasing load of ASFRPC specimen. Thirdly, the fiber distribution of ASFRPC is uniform at the fracture, most of which are perpendicular to the main crack direction.Besides, the anchorage length is also long, and the bridging effect is significant at the fracture. In conclusion, considering the equivalent bending stress and energy absorption capacity of ASFRPC specimens, the mechanical properties of aligned steel fiber specimens perform best when the fiber content is 2% and the fiber length is 20 mm.