The effect of RE content and cold rolling plus annealing on the microstructure and corrosion resistance of Al-Mn-RE alloy were studied by means of metallographic microscope, scanning electron microscope and electrochemical workstation. The results show that the eutectic phases with different sizes and irregular shapes can be seen in Al-Mn-xRE alloys. With the addition of different RE content, the amount of Si containing eutectic increases, the long strip-like eutectic structure was refined and gradually transformed into spherical or short rod-like structure. When RE content reaches 0.25% or more, the eutectic structure begins to coarsen. With the increase of RE content, the corrosion potential and pore size of Al-Mn-xRE alloys increase, however, the corrosion potential of Al-Mn-0.18RE alloy shifts positively and then negatively, whilst the corrosion current density decreases first and then increases. In fact, the alloy with 0.18% RE presents the maximum corrosion resistance. The corrosion potential and pitting corrosion potential of the Al-Mn-0.18RE alloys subjected to different treatments may be ranked the following order: homogenization>cold rolling+325 ℃ annealing>rolling>cold rolling +475 ℃ annealing. With the increase of RE content, the corrosion rate of the Al-Mn-xRE alloys subjected to cold rolling and annealing at 325 ℃ decreases first and then increases, and reaches the minimum value when the RE content is 0.18%. The corrosion resistance of the rolled Al-Mn-0.18RE alloy is lower than that of homogenized Al-Mn-0.18RE alloy, but the corrosion resistance can be improved by subsequent stabilization annealing at 325 ℃.