Aluminum (Al) alloy microelectrodes were designed and installed in an impingement jet system to investigate the effect of fluid hydrodynamics on Al alloy corrosion in a flowing ethylene glycol–water solution by electrochemical measurements and computational fluid dynamics simulation. Results demonstrate that fluid hydrodynamics, in particular, the fluid flow velocity and shear stress, play an essential role in corrosion of Al alloy. The microelectrode located at the center of the sample holder is associated with the most stable state, while the one at the edge of the holder has the most active state. The electrochemical activity of the Al alloy microelectrode, indicated by the anodic dissolution current density, is directly related to the velocity of fluid flow and the shear stress.