Due to big structure and complex process for some large-scale products (such as planes and rockets), the workers have to try many times and move around in the products to accomplish the assembly operations for high-precision requirements. Thus, the efficiency is low and the cost is high in the assembly process. To deal with that, the virtual assembly (VA) system for large-scale products is developed in this paper. First a new VA environment considering human activity is set up, and then a hierarchical assembly process list (HAPL) model and a dynamic constraint recognition algorithm is proposed to realize exact placement for large-scale products in VA system. Finally, the method is verified by the development VA system which successfully applied in the process of satellite assembly. Moreover, the method can be used in the common VA systems for assembly planning.