Abstract: The Antarctic Observatory of China contains an optical/infrared telescope with a diameter of 2.5 m primary mirror. The telescope is made in China and needs to be transported to the Antarctic Observatory in the form of large assembly. From Zhongshan Station in the edge of the Antarctic continent to Kunlun Station in the interior of the continent, the telescope needs to be transported by sled, which vibrates violently in some regions. In this paper, the vibration isolation system of the telescope's 2.5 m primary mirror module for transportation was researched. Firstly, the theoretical model of vibration isolation system was established and the performance of two-stage vibration isolation system was analyzed by the four-terminal parametric method. Secondly, the historical data from the Antarctic inland expedition team in the sled transportation was studied and the allowable dynamic condition of the primary mirror module was calculated by finite element method(FEM) considering the non-uniformity of the bottom supporting force. Thirdly, a two-stage vibration isolation system consisting of a leverage buffer structure and a polyethylene foam structure was proposed. Finally, the performance of this vibration isolation system was researched with FEM simulation and multi-body system simulation. The results show that the vibration isolation system proposed in this paper can meet the requirement of the mirror's transportation. In the finite element model, when the most extreme impact signal is loaded which is acquired by the Antarctic inland expedition team form the sled transportation, the maximum acceleration of the primary mirror module is less than 5 times acceleration of gravity which is a security value coming from the dynamic analysis of primary mirror module, and the Z-direction moving range of the module is about 1.2 m. So the vibration isolation system has practical value. This system can be used in the transport of the primary mirror module of the 2.5 m telescope to the Antarctic inland. The vibration isolation system proposed in this paper is valuable for transportation of other fragile structures.