Magnesium alloy and aluminum alloy composite materials not only have good conductivity, heat conduction, corrosion resistance and formability of magnesium alloy and aluminum alloy substrates, but also have the advantages of beautiful appearance, light weight and precious metal saving. In addition, magnesium has active chemical properties and low equilibrium potential, which leads to poor corrosion resistance of magnesium alloy. Both disadvantages restrict the further development of magnesium alloy. However, aluminum alloy has the characteristics of corrosion resistance, high strength, easy processing and no brittleness at low temperature. However, the application of magnesium alloy is limited due to its poor plastic deformation ability at room temperature and difficulties in processing and forming. Therefore, the author attempts to analyze the influence of annealing temperature on the diffusion bonding layer of magnesium alloy and aluminum alloy by using finite element technology, so as to take corresponding measures in processing to prevent magnesium alloy chip combustion or explosion accidents.