Abstract: Aimed at the problems of poor interactivity and weak operational experience in current virtual assembly systems, a virtual and real interaction AR assembly system is developed based on augmented reality technology. Taking reducer disassembly as an example, combining collider and separation axis theorem, the collision detection method between models was designed to reduce online calculation workload and realized fast dynamic assembly simulation. Based on the image recognition, the triggered detachment recognition method solved the problem that the virtual model position was not controllable in the traditional detachment recognition process. Experimental results show that the system can not only realize real-time virtual real interaction assembly simulation, but also enhance the assembly interaction and sense of operation.