In water resource allocation engineering, the flow velocity is the most important factor influencing corrosion damage in the elbow sections of steel pipes. This study reports the effect of flow velocity on the corrosion performance of carbon steel at different pipe elbow section locations though which freshwater flows. The corrosion damage of carbon steel was accelerated in flowing freshwater; however, this accelerating effect was weakened with high flow velocity. Furthermore, the corrosion rate at the outer wall was higher than that of the inner wall of the pipe elbow section with low flow velocity; when high flow velocity was used, more uniform corrosion damage was found at the pipe elbow section. The influence of flow velocity on the corrosion performance of the carbon steel was closely related to the hydrodynamic parameter distribution and the nonuniform accumulation of corrosion products at different locations of the pipe elbow section in flowing freshwater.