Abstract: Dynamic triaxial test is a vibration test, in which, the sample is consolidated by axisymmetric triaxial stress in the undrained condition.Through the test, dynamic shear modulus ratio and the damping ratio of soil samples can be determined.Dynamic shear modulus ratio and damping ratio of soil samples are two important parameters in soil dynamics characters and indispensible for seismic safety evaluation and seismic response analysis of the soil layer in engineering sites.In order to reduce time limit, improve work effiency and submit report timely and accurately, according to our years of experience in soil test, we conduct a comparison test on cohesive soil that reaches above plastic condition and achieve perfect test results.