Abstract: A numerical analysis method describing the cyclic degradation for suction bucket in soft soil is developed by employing a perfect elastic-plastic soil model with Tresca yield criterion and the proposed stiffness degradation model of soft clay. The USDFID subroutine is encoded to realize this method. In order to verify the rationality of the numerical method,the three-dimensional numerical simulation is performed for the cyclic loading model test of the tensioned suction bucket foundation. In addition,bearing characteristics of the suction bucket foundation considering the cyclic degradation is also analyzed. Research results show that the numerical method can simulate the cyclic deformation process of suction buckets in soft clays,and predict the nonlinear hysteresis and cyclic accumulation of the load-displacement curves,as well as predict the cyclic bearing capacity of buckets. Increasing the diameter or length of the suction bucket can reduce the degradation of the foundation stiffness to a certain extent. Under the condition of the same steel consumption,increasing the length can improve the cyclic bearing capacity more significantly than increasing the diameter.