Abstract: In Jordan, considerable amount of construction activity is carried out at relatively shallow depths where soil is likely to be unsaturated and subjected to low stresses level. One particular example is the pavement. The occurrence of damage to road founded on unsaturated subgrade in Karak, Jordan is due to the collapse of the soil structure upon wetting-wetting process, has come to be well recognized. It has recently become apparent that these unsaturated soils can cause damage to roads because of the change in the shear strength of unsaturated soil as the degree of saturation changes. An experimental program was designed to study the behavior of unsaturated soil as the degree of saturation changes. Direct shear was used for the testing program on unsaturated silty clay that was carried out as part of this research program. Specimens were prepared with initially different saturation to simulate different climate conditions. The results showed that; as the initial degree of saturation increases up to 50%, the shear strength increases and then decreases as the initial saturation increases beyond 50%. Also, as the normal stress and the density increase the strength increases.