Abstract: Based on single-line method and double-line method, wetting tests on two kinds of coarse-grained materials, granite and metamorphicrock, are performed by use of a large-scale triaxial apparatus. According to the test results, there are some differences between the single-line method and the double-line method. The single-line method is better to study the wetting characteristics of coarse-grained materials. The method to obtain the wetting defomation in the single-line method is established. Based on different wetting deformation regularities of coarse-grained mateials, the relationship between strain and stress in the wetting tests is obtained. As a result, the wetting model and model parameters of coarse-grained materials are proposed and used as the basis in the analysis of wetting deformation of coarse-gained materials.