The researchers conducted tests on unsaturated undisturbed loess Q2 to understand its strength and deformation properties. They found that the loess Q2 fails in shear with a rupture angle between 55 and 61 degrees. Under low pressure, it expands, while under high pressure, it shrinks. As pressure increases, the stress-strain curves change from perfectly plastic to weak strain softening. A method was suggested to determine the field stress of loess Q2 under triaxial shear conditions. The deviatoric yield stress has a logarithmic relationship with net mean yield stress as pressure increases.