Abstract: The strength of a natural clay is affected by its structure and anisotropy. The consolidated-undrained shear test with a constant principal stress axis deflection angle is conducted, where the consolidation pressure is 100 kPa and the constant deflection angle of the principal stress axis is 0°, 15°, 30°, 45° and 60°. And the influences of different constant principal stress axis deflection angles on the consolidated-undrained shear strength and the cumulative pore pressure of the saturated soft clay are analyzed. The total stress path of the total stress-controlled constant principal stress axis deflection angle shear test is derived. The integration program of the total stress-controlled shear three-dimensional point is developed. By comparing the calculated and test results of the shear strength at the constant principal stress axis deflection angle of the saturated soft clay under consolidated-undrained conditions, it is shown that the influence of the anisotropy on the shear strength of the soil is well revealed.