Abstract: The unsaturated state is an important factor affecting the mechanical properties of soil. In view of the lack of researches on soil-water characteristics of coarse-grained accumulation soil, a large unsaturated coarse grained soil triaxial test system is first introduced. On the basis of experimental researches, the methods and control standards for soil-water characteristic (SWCC) tests on the coarse-grained accumulation soil are summarized. Then, the variation of SWCC of the coarse-grained accumulation soil with different fine-grained soil contents is summarized. Finally, on the basis of the AP model, the determination method for the key parameter α is systematically analyzed, and the optimal method to predict the SWCC of coarse-grained accumulation soil by using the AP model is given.