Compared with the traditional semi-submersible platform, the deep-draft semi-submersible platform has better motion stability and is more suitable for deep-sea combustible ice exploitation. In this paper, the deep-draft semi-submersible platform, which is applied to the 1500m operation water depth, is taken as the research object. Through the hydrodynamic model test, the hydrodynamic performance is deeply studied, and compared with a typical shallow-draft semi-submersible offshore platform. The results show that the natural period of rocking and heave motion of the deep-draft semi-submersible is significantly smaller than the shallow-draft offshore platform, and the motion response of the former is greatly reduced in the wave frequency range. The maximum rocking motion is 1.54°and the maximum horizontal motion is 13.12m under the operating sea condition, which has excellent motion performance can meet the engineering needs of deep-sea combustible ice exploitation.