Abstract: A series of undrained and drained cyclic triaxial tests have been done to study the cyclic behavior of a Nanhai marine silty soil. In particular, importance of the effect of drainage on cyclic behavior was investigated. The experimental results show that drainage has a hardening effect on normally consolidated marine silty soil, it increases the undrained static strength, and decreases the generating rate of cyclic pore pressure and hence increases the cyclic resistance. On the basis of the previous and present research work, a method for predicting the cyclic properties of silty soil under various drainage conditions is developed in this paper. Comparisons of predictions with experimental results show generally favorable agreement.