Fluid scour is one of the major causes for bridge failure. To prevent this type of failure, even the catastrophic accidents, it is necessary to make a further study on the effect of fluid scour on mechanic behavior of bridge pier. In this paper, the 3-D finite element model of piled pier and soil interaction is established. The scouring process is simplified for the soil excavation, and the effect of scour on overall stability of piers and bearing behavior of piled pier structure is simulated and discussed. The curves of horizontal, vertical displacement and carrying capacity under various scour depths are drawn in the article. It demonstrates that the effect of fluid scour on piled pier bridge is bad. With these analyses, some useful conclusions in engineering practice are obtained.