Fluid field can have significant effects on corrosion rates of steels. The objective of this paper is to investigate erosion-corrosion mechanisms of J55 steel and the effects of local hydrodynamic factors, in particular, the fluid flow velocity on J55 steel’s service life. A new experimental setup was developed to specifically simulate the actual hydrodynamic conditions of Huanghe (Yellow) River valley. Computational fluid dynamics (CFD) model was adopted to characterize the hydrodynamic factors, such as the flow rate, the turbulence kinetic energy and the shear stress, and their effects on the corrosion behavior of J55 steel. Corrosion morphology was analyzed. Results show that the erosion rate increased with the flow rate and the resulting corrosion pit became smaller and deeper. Through the research results of this paper, it could provide some technical supports for the scientific and rational exploitation of brine.