The dispersion and randomness of concrete cracking under compressive loads make it challenging to predict the diffusion rate of chloride ions. In this paper, the cohesive element method was employed to quantitatively calculate and determine the form and width of dispersed cracks in concrete. These results were found to be consistent with the real concrete crack forms obtained using digital image correlation (DIC) technology. The findings indicate that both the form and width of the cracks significantly impact the diffusion of chloride ions within the concrete. Chloride ion diffusion is enhanced when the cracks are closer to the penetration side or when there are more cracks present in the concrete. Additionally, an increase in axial load amplifies the randomness of chloride ion distribution at the same penetration depth. While coarse aggregates can impede chloride ion penetration, wider cracks lead to a higher concentration of chloride ions within the concrete. Our results contribute to a deeper understanding of chloride ion diffusion in cracked concrete under varying stress levels.