16 kinds of wet soil with different particle diameter and moisture were used to study the changes in adhesion characteristics between soil-touching components and soil during soil drying. The slope sliding test of metal plate （65Mn steel） was conducted to measure the relationship between the particle diameter and moisture of soil and the adhesion between metal soil-touching components. The microstructure of soil samples was analyzed with microscope. The adhesion phenomena between soil and metal plates during the drying process was observed. The results showed that the "traces" produced by soil with a moisture of 30% and 40% sliding on the metal surface were more obvious than those by soil with a moisture of 10% and 20%. Among them， the soil with moisture of 30% and the particle diameter of 10-50 μm had the maximum adhesion. The differences in particle diameter， overlooking perimeter， and overlooking area increased with the increase of moisture and particle diameter before and after soil drying. During the drying process， the gap between the particles gradually decreased， some particles had "diffusion"， "contraction" and other phenomena， some particles occurred relative displacement. The soil with moisture of 30% and the particle diameter of 10-50 μm had the maximum relative displacement of 13.78 μm. The soil adhesion first increased and then decreased with the increase of moisture. As the particles decreased， the soil adhesion gradually increased. When the moisture was below 30%， the greater the particle displacement before and after drying， the stronger the soil adhesion. It is indicated that the soil with moisture of 30% and particle diameter of 10-50 μm exhibits the strongest adhesion and the phenomenon of maximum relative displacement of particles during soil drying.