Study and evaluation of permeability of concrete surface are related to quantization of the secondary area of the concrete surface layer and its performance characterization. Some parameters relating to concrete layers are studied. Three main concepts including the fault displacement from the inner surface x, the median of fault displacement from the inner surface z, and the unit fault layer from surface Z is proposed. Then the division method, characterization method and distribution model of unit cross section layer S as well as the performance parameter and the distribution characterization method of the unit cross section layer are established. The research purpose and significance of permeable surface layer based on chloride ion are clarified. The test result of chloride ion mass fraction in unit cross sectional layer is analyzed with the characterization methods of S and its CHS. It is known that the surface layer thickness affecting the permeability of concrete is 2.03.0 mm. Z3 =2.5±0.5 is a special fault. The fault magnitude of stratified sampling is sub millimeter level. The thickness of permeable surface layer is limited to 10 mm. The apparent distribution model of CHS is an exponential function CHS,b z(x). The benchmark of CHS at the inner surface of permeable layer surface is different from that at outer surface. The distribution model of the position and distribution of fault as well as the structure layer partly relating to the layers are proposed. At the same time the characterization method for CHS and its distribution are put forward.