Abstract: The open caisson foundation is widely used in marine drilling platforms, bridge foundations and wind turbine foundations due to its large bearing capacity and high lateral stability.While the dynamic response of the open caisson foundation under earthquake still remains unclear, the nonlinear dynamic stress-strain relations obtained from the dynamic traxial tests are implanted to numerical software in this study.The lateral dynamic response of the open caisson foundation under different types of site soil, earthquake peak accelerations(PA)is investigated.The results indicate that the relative lateral displacements of structure and site soil increase with the PA linearly and exponentially, respectively.The site soil constrains the caisson foundation when it is in good condition or the PA is relatively small, which means α>1.Vice versa, the structure will be pushed by the foundation soil, which will endanger the stability of the foundation.