To study the mechanism of chloride ion permeation in recycled concrete，a mesoscale model of double-cracked recycled concrete was established using MATLAB，aiming to reveal the superposition effect of double cracks on chloride penetration and the impact of adjacent damage zones around the cracks on penetration behavior was investigated. The model included various components，such as new mortar，old mortar，new interfacial transition zone，old interfacial transition zone，original aggregate，double cracks，and damage zones. Through systematic analysis of factors such as the width and length of the double cracks，the dimensions of the damage zone size，crack shape，and crack spacing，it is found that the superposition effect of double cracks has a significant impact on chloride ion concentration. When the spacing between cracks exceeds the critical value，the chloride ion penetration between the two cracks will no longer interfere with each other. The research results provide a theoretical basis for a deeper understanding of the chloride ion permeation mechanism in recycled concrete.