Abstract: After simply remade DTC-199 cyclic torsional load triaxial apparatus, the effect of principal stress axle rotation to axial residual deformation and dynamic shear residual deformation of compacted loess with cyclic dynamic load is researched. The results show that: with the initial principal stress direction angle increases, the axial residual deformation from the compression state gradually transits to the elongation. The vibration times has significant impact on the shear residual deformation. Shear deformation increases with the vibration times increases and shows an increasing tendency as the initial principal stress direction increases.