Filling position of carbonized sediments in the pore structure of cementitious materials was investigated. The effect of the carbonation on pore size distribution and permeation rate was analyzed. Additionally， based on the composite probability pore size distribution， nonlinear pore size distribution transformation models and permeation rate prediction models for cementitious materials after carbonation were constructed. These models were then confirmed using experimental data. The results indicate that the prediction accuracy of water permeation rate can be improved in consideration of the changes in porosity and pore size distribution after carbonation. The change in pore saturation during carbonation alters the filling position of carbonized sediments within the pore structure， leading to differences in pore size distribution and permeation rate after carbonation. Compared to the single pore compaction process， the rate of decrease in cementitious materials permeation rate is slower during the iterative compaction process.