Assembly is an essential part of the product life cycle. Inefficient assembly has a direct impact on the effectiveness and quality of the product. One of the main problems of current on-site assembly operations is clear and efficient guidance, which consists of two aspects: the lack of efficient reuse of existing data and confusion in the form of presentation. In order to reduce errors and the time required to perform assembly tasks, we aim to propose an integrated lightweight 3D interactive method to guidance in assembly process. It enables the reuse of previous process design and simulation stages, which can reduce the duplication of content and enhance the content preparation efficiency. At the same time, the method is platform-independent, does not rely on high-performance workstations and can be presented on mobile, cross-platform. One case of disassembly the graphic card in the computer is presented to verify the method.