Abstract: Based on the architecture description method and modularization description method, combined with the characteristics of nuclear reactor research and development and the theoretical method of system engineering based on models, the architecture design and key technology study of modularization for the digital reactor platform are carried out. Through the analysis of the models, algorithms, data, and processes carried by the digital reactor platform, as well as the complex heterogeneous software and hardware environment centered on the supercomputer, the business architecture, application architecture, data architecture, and technical architecture design of the digital reactor platform are proposed to guide the research and development of the digital reactor platform. Through the functional verification of the digital reactor platform, it is shown that under the guidance of the architecture of the digital reactor platform, the platform has reconfigurability, reuseability, scalability, and robustness. The developed functions can meet the engineering requirements, and its architecture design practice has an important guiding significance for the subsequent design of complex system platforms.