The invention discloses an aluminum-silicon alloy for a cylinder liner and a preparation process of the aluminum-silicon alloy. The aluminum-silicon alloy is prepared from the compositions in percentage by mass: 12-15% of Si, 1-5% of Cu, 1-4% of Ni, 0.5-2.5% of Mg, 0.01-0.1% of Sr, 0.1-1% of a mixed rare earth element RE, less than 1% of impurity elements, and the balance of Al, and the sum of thetotal amounts of the compositions is 100%. According to the aluminum-silicon alloy for the cylinder liner and the preparation process of the aluminum-silicon alloy, the aluminum-silicon alloy with the silicon content close to an eutectic point is used as a matrix, only Cu, Ni, Mg and other elements are selectively added, the modification process of an alloy phase is simplified, and the cutting action of the alloy relative to the matrix is weakened; due to the low silicon content, primary silicon phases are few and small, pressure casting molding processes (such as extrusion casting, ordinarypressure casting and low-pressure casting) are adopted, the solid solubility of silicon in alpha-Al is increased, an Sr/RE composite modificator is used for modifying eutectic silicon and the alloy phase, the performance of the aluminum-silicon alloy is comprehensively improved, combined with an optimized T6 treatment process, a product has the advantages of smaller specific gravity, lower linearexpansion coefficient, and higher abrasive resistance and volume stability, and the application requirements of the cylinder liner are met.