1D rectangle spur dike, 2D trapezoid spur dike and 3D deposit body model were used to investigate the influence of structures with different dimensions on water surface profiles and 3D time-mean velocities under the same flow condition by flume experiments. The experimental results show that, (1) for the same occupied width ratio of the structures, the actual flow resistance area induced by the trapezoid dike is the largest and it has the most intensive resistance impact on the upstream flow due to the existence of the first recirculation zone. The rectangle spur dike and deposit body have a medium and least flow resistance impact, respectively. (2)With the same flow resistance area ratio(flow resistance discharge ratio), the rectangle dike has a better ability to accelerate the flow along the channel near the narrowed cross section and detour the flow to the bank than the trapezoid dike, but the flow around the trapezoid dike has a higher vertical velocity. (3)When the length of the structures keeps the same along the flow direction, the longitudinal, horizontal and vertical velocities around the deposit body are lower than that around the rectangle dike due to its smaller maximum cross-sectional area. As a result, the factors commonly applied to evaluate flow resistance characteristics, such as the occupied width ratio, the flow resistance area ratio and the flow resistance discharge ratio, cannot entirely represent the influence of the structures on river flows.