In the process of disassembly and assembly of mechanical parts, there are problems such as large equipment investment, high loss, high risk, and low disassembly efficiency, this study uses mixed reality technology to design a virtual disassembly and assembly system. Among them, the disassembly logic is the core of the disassembly system, and the universality of the disassembly system depends on the design of the disassembly logic. In order to solve the problem of poor universality of the virtual disassembly system, this study analyzes and summarizes the connection and assembly relationship of common mechanical models, and designs a graph-based traversal algorithm. The data structure is used to express the logical relationship of each model, and experiments are carried out on the disassembly and assembly of special valves and six-joint manipulator. The experimental results show that the disassembly and assembly logic solved the problem of definability and versatility of the disassembly and assembly sequence, and can perform virtual disassembly and assembly of the model components according to the process flow, and finally realize the versatility of the virtual disassembly and assembly system.