With triaxial apparatus specially made for unsaturated soil

the tests of shear strength and soil-water characteristic curve of unsaturated loess under different water contents are performed. The test data show that the shear strength of unsaturated is bigger than that of saturated loess; and it decreases with increasing water contents and lessening matric suction

and vice versa. The shear strength of unsaturated loess will be close to that of saturated loess when water content is saturated. The internal friction angle changes little while water contents change

but the total cohesions change greatly under different water contents. The loess has smaller matric suction and total cohesions at high water contents. According to the results

the model of shear strength of unsaturated loess is proposed. The parameters can be derived easily. The error is small

and the model meets the requirement of calculation of sheer strength of unsaturated loess.