Abstract: The paper explores several methods measuring degree of saturation in unsaturated soils.Different test methods for the degree of saturation in unsaturated soils can result in different results.According to the tests by GDS triaxial cell,the paper compares and analyzes these methods.It is pointed out that pre-assumption of soil grain volume being invariable is logical. Therefore,the change of specimen volume is equal to the change of soil specimen pore.The direct method is an effective method for measuring degree of saturation.