The work aims to meet the needs of research and development, later-stage maintenance and operation training, etc. of new products. Taking Makerbot Replicator2 3D printer as an example, accurate modeling was done in 3D modeling software SolidWorks through actual measurement. Then, model optimization was conducted in 3ds Max and finally imported into the VRP to complete the fabrication of virtual assembly system. The system could display the internal and external structures and the assembly process of the entire 3D printer. The combination of virtual assembly technology and 3D printer can present the overall structure and function of the 3D printer in digital form, without being restrained by objective conditions. It provides a brand-new solution for the design, improvement, maintenance and management of industrial products, and has certain applicability in the existing 3D printers of the market.