Recently, a possibility of the surface treatment material is expected as an integrated control method for various degradations of concrete structure. However, as experimental results, although water permeability of the concrete could be improved due to the surface treatment material, the scaling of surface layer was accelerated under freezing and thawing cycles. Furthermore, the mechanism of scaling acceleration has not been clarified yet. Therefore, in order to clarify the mechanism accelerating the scaling of the treated concrete, the behavior of variations in the moisture and ice contents in the concrete were investigated especially based on a simulation analysis using a simultaneous heat and moisture transfer equation for a three-phase system. The analysis simulated the freezing-thawing process in the RILEM CIF/CDF test. And the mechanism accelerating the scaling is discussed based on the differences of the freezing behavior due to the infiltration depth of the surface treatment material. As the results, in the case of the smaller infiltration depth, it has been clarified that the reason to accelerate the scaling is the increasing of the ice content at the boundary between the treated and untreated regions.