Aiming at the shortcomings of traditional assembly process design and immersive virtual assembly system, the architecture of Desktop Virtual Assembly System (DVAS) for interactive assembly process planning is presented. The key technologies such as data conversion and reconstruction of assembly models, assembly intention recognition and assembly control navigation are studied. The lightweight storage of assembly models’ data and the intelligent constraints recognition are realized. The problem of assembly operations resulted from the lack of immersion is solved by movement navigation. The algorithms were proposed and applied to the DVAS prototype, and an application case is studied to demonstrate the effectiveness of the system.