China's space technology has gradually improved from the early stages' introduction, absorption and re-in-novation based on backward design to independent innovation based on forward design. It is necessary to develop a new approach of systems engineering to improve the quality and efficiency of space systems design considering the large number of original design problems expected in the future. Adopting Model-Based Systems Engineering (MBSE) and Digital Twin method are important development initiatives in the field of modern engineering design. In the initial phase of system design, it is necessary to generate firm system architecture models based on the needs of stakehold-ers. The quality of the system design in this phase has a great impact on the detailed design and implementation for the subsequent system, and also plays an important role in the performance, development progress and cost of the whole system. Through the collaboration of cross-professional teams, modeling and model execution, comparing the model execution with expected results, MBSE has enabled digital model-level verification and validation before test verification and validation based on physical products, thus improving the design exactness, completeness and greatly reducing design errors or defects. This paper explores the logical ideas behind modeling of system architectures in order to pro-mote the adoption of MBSE in the field of space systems.