The dry tree production and drilling Top Tensioned Riser (TTR) systems have been widely used with Tension Leg Platforms (TLPs) and SPAR in deepwater applications. However, the conventional Semisubmersible is not suitable for dry tree applications due to the large heave motion of the floater. In order to incorporate the dry tree system to the Semisubmersible, Magneto-Rheological (MR) dampers are combined into TTR systems. The MR damper is a controllable device which can interactively change the damping force correspond to various external loadings. In this research, the motion of Dry Tree Semisubmersible (DTS) with MR damper is to be studied by numerical simulation and the results are to be compared with the model test results.