Abstract: Dynamic and static triaxial tests are carried out to study the patterns of undrained s trength development of undisturbed and remolded clay after cyclic loading. The results show that the undrained strength of undisturbed saturated clay can degrade after cyclic loading, when the dynamic axial strain is higher than 3%, the reduction factor increases firstly and then keeps steady; the reduction factor keeps at low level when the ultimate pore pressure ratio stays at 0.5 to 0.7, and it will rise rapidly if it is higher than 0.7; and with the increase of the reduction factor β, the stress paths transform from normal consolidation to lightly quasi-overconsolidation, then to heavily quasi-overconsolidation. The strength of remolded saturated soft clay hardly changes after cyclic loading.