Abstract: The long-term deformation under dynamic cyclic loading is a problem drawing attention in engineering practice. Due to the limitations of the experimental conditions, the results obtained in the study of long-term dynamic deformation are limited, but the rheological results are relatively more. In this work, the marine soft soil of the Tianjin Binhai New Area is used as the research object, and the TSS10 soil triaxial rheological test for the rheological test and the GCTS hollow cylinder torsional shear apparatus for a large number of dynamic cyclic loading tests are carried out. The experimental results show the under the same confining pressure, when the dynamic stress is equal to the static stress, the dynamic accumulative deformation is similar to that of the long-term static deformation, and the difference is that the dynamic accumulative deformation is slightly larger than that of the static deformation. Based on the static rheological element model, together with calculating deformation difference between the dynamic and static load under the same condition, the long-term dynamic deformation prediction formula is established and used to verify the experimental data. The results show that the prediction formula is more reasonable, which can provide theoretical support for engineering constructions.