Abstract: Aiming at the design and management problem of body-in-white assembly process,a tree-relation mixed model is put forward to re-present the information of body-in-white welding and assembling process.Based on this data model and man-machine interactive graphic simulation platform,a visual in formation model for car-body assembly process is build.The fesibility of car-door weld-assembling process is analyzed using this model.The result shows that this model is able to represent various information in assembling and spot welding processes visually and integrally.The model can be used for the structure design of body-in-white,welding-process analysis and design,process information management,quality control,and personalized selling.