Abstract—The coupling characteristics are always taken into consideration when designing the hydraulic Stewart platform. In this paper, the large hydraulic Stewart platform is studied on the coupling dynamics. A combined simulation method is developed in which the hydraulic system model is built in software AMESim, and the parallel mechanism system model is built in software SimMechanis. With the simulation system the dynamic coupling characteristics are studied under alternative situations depended on the dynamic consistency of the six hydraulic cylinders. This method which is universal in different huge hydraulic Stewart platforms is of high accuracy, it provides a theoretical research technique of the coupling study for the Stewart platform, in addition, this method can pre-estimate the coupling state, and therefore it ensures the accuracy and the reliability of the design scheme.