MagnesiumMagnesium foams have excellent mechanical performance but lower corrosion resistanceCorrosion resistance, limiting the development and application of magnesiumMagnesium foams. In this study, AZ91 magnesium alloyAZ91 magnesium alloy foams with six differentSn Sn content (0, 0.05 wt%, 0.10 wt%, 0.15 wt%, 0.20 wt%, and 0.25 wt%) were successfully obtained using the metal powder metallurgy method. The effects of Sn addition on the pore, mechanical behavior, and corrosion resistanceCorrosion resistance of AZ91 magnesium alloyAZ91 magnesium alloy foam were investigated by X-ray diffraction (XRD), electron microscopy (EM), compression and hardness testing machines, and corrosion resistanceCorrosion resistance test. The results indicate that Sn leads to the formation of Mg2Sn and increases relatively β-Mg17Al12, which refines the alloy grain and densifies the pore wall. The mechanical propertiesMechanical properties of AZ91 magnesium alloyAZ91 magnesium alloy foam in ambient temperature reach the highest with the addition of 0.10 wt% Sn, and the highest corrosion resistanceCorrosion resistance appears at 0.15 wt% Sn.