The engineering properties of coral sand are special, so it is important to study the bearing characteristics of coral sand foundation for island construction. The influences of relative compactness and water content state on the bearing deformation characteristics, particle breakage, layered settlement and the pattern of earth pressure transfer of coral sand foundation are studied through the plate loading model test of coral sand foundation under different working conditions, such as different relative compactness (50%, 65%, 72%, 80% and 85%), different water content states (dry or saturated) and water level variations. The results show that the bearing capacity of coral sand foundation increases and the settlement decreases with the increase of relative density in dry condition. The coral sand particles are broken more significantly while the relative compactness is greater than 80%. The earth pressure directly below the bearing plate decreases with increase of depth. The bearing capacity of coral sand foundation in saturated state is about 44% of that in dry state, the settlement in the failure is about 2 times of that in dry state, and the influence of two times of water level variation on the bearing capacity and settlement of foundation is small. At different locations from the center of the bearing plate, the developments of the layered settlement of coral sand foundations in saturated, water level variation and dry state are different. The pattern of earth pressure transfer is similar in the three states.