Abstract: Based on the shortcomings of the traditional fracturing ball, the soluble magnesium alloy with excellent properties was prepared by casting. This study investigated the effects of aluminum elements content on the microstructure, solubility, and mechanical properties. The results reveal that the microstructure of soluble magnesium alloy comprises the following two phases:α-Mg and β-Mg₁₇Al₁₂. β-Mg₁₇Al₁₂ increases with an increase in aluminum content and continuously distributes in the α-Mg grain boundary. In addition, α-Mg becomes coarse. The soluble magnesium alloy could dissolve in the KCl solution, and the dissolution rate increases with an increase in KCl concentration until the rate reaches a maximum at 3% (mass fraction) KCl; the rate subsequently decreases after reaching this maximum. In addition, the dissolution rate increases with an increase in aluminum content until the dissolution rate reaches 7.42 mg·h^-1·cm^-2. The corrosion product of the soluble magnesium alloy is finer, and the median grain size is 38.691 μm, which ensures a smooth discharge of products, and the corrosion products are Mg₁₇Al₁₂ and Mg(OH)₂. The compressive strength of the soluble magnesium alloy could reach 430 MPa and the material breaks when the deformation reaches 3.0%, which the plasticity of this material reduces with increased aluminum content.