55%Al-Zn-1.6%Si coating with different amounts of Mg and RE is prepared by the hot dip plating method. The morphology and corrosion resistance are charactered by scanning electron microscope (SEM), salt spray test and corrosion weightless test, respectively. The influence of the amount of Mg and RE in 55%Al-Zn-1.6%Si alloy coating on corrosion resistance is studied. The corrosion mechanisms are discussed based on the X-ray diffraction (XRD) results and the electrochemical tests of 55%Al-Zn-1.6%Si-Mg-RE and 55%Al-Zn-1.6%Si coatings. The results show that Mg can refine the grains and strengthen the grain boundary, and the best addition amount of Mg is 1.5%. RE can reduce the liquid surface tension, refine the grains and improve the corrosion resistance, and the best addition amount of RE is 0.12%. The addition of Mg and RE causes Al preferred crystal to decrease, so that the surface potential of coating tends to be homogenization, and the corrosion speed of micro cell is reduced. The corrosion potential of 55%Al-Zn-1.6%Si-1.5%Mg-0.12%RE coating is -0.983 V and the corrosion current density is 16.91 μA/cm2.