To provide support for the road, bridge and foundation treatment of Boubyan Seaport Project Stage-I in Kuwait, we performed in-situ tests on the soils along the highway and railway line on Boubyan Island, carried out laboratory tests on 199 undisturbed samples, and also conducted direct shear tests on disturbed soil samples before and after eluviations. Test results and analysis show that the soils on Boubyan Island belong to silty clays and coastal saline soils with high content of chloride, and has a little property of  sandy soils. Its engineering properties include low moisture content, low Atterberg limits, low sensibility, low shear strength (easily disintegrated), and high compressibility. Natural formation, soluble salt content and surface charge density are main causes of these properties. 