The International Thermonuclear Experimental Reactor (ITER) is one of the largest international cooperative projects with many participants from different research groups in institutes and universities all over the world and is expected to achieve nuclear fusion energy output and to be operated in steady state with tritium self-sufficiency. The conventional design of the ITER-type facility always directly faces challenges of operation difficulties in the assembly and maintenance processes considering that there are collision interference and corresponding precision problems within the constrained space; consequently, it is not possible to provide for research purposes qualitative information for human intuition and quantitative contents with professional advice. Therefore, it is necessary to find a better solution for researchers and operators to get a highly efficient group-based work form without being blocked for reasons of geography. In this context, virtual reality technology has been introduced in the digital assembly and maintenance training platform of the ITER-type mock-up at the Institute of Modern Physics, Chinese Academy of Sciences, and it has many useful features, including real-time collision detection in assembly tasks with simplified trigger mesh structures by means of the ray-casting method, and three-dimensional visualization of the topological structure in the welding and brazing maintenance using the UV unwrapping and remapping methods considering the conversion process from digital values to gray-scale texture, which can meet the flexible and diverse design requirements and provide feasibility of training at the University of Chinese Academy of Sciences.