The invention relates to a deformation annealing process for Er-containing aluminum magnesium alloy plates, which belongs to the technical field of nonferrous metal. A Er-containing aluminum magnesium alloy hot rolled plate is subjected to recrystallization annealing for 2 hours at 350 DEG C, then, the aluminum plate hot rolling is carried out, 55 to 80 percent of cold deformation quantity is preserved for the final finished plate, and then, the intermediate annealing is carried out for 2 hours at 350 DEG C; and the aluminum plate after the intermediate annealing is processed into the finished product thickness through cold rolling, the deformation quantity is 55 to 80 percent, finally, the stable annealing at 120 to 220 DEG C is carried out, and the annealing time is 1 to 3 hours. Through Er addition, tiny dispersed Al3Er particles are separated out from base bodies, the stress reinforcement effect is enhanced, and the separation position and form of beta phase (Mg2Al3) are controlled, so the Er-containing aluminum magnesium alloy plate with higher strength, stability and good intercrystalline corrosion performance is obtained.