This system is a virtual assembly one of a type of cylinder cover which based on OSG. The system uses OSG the 3Dgraphics engine to realized model rendering, human-computer interaction, stereoscopic displaying, parts dragging, animation path and other related technologies. At the same time using CEGUI to achieve the interaction of the virtual scene and a graphical interface .Users can directly use the mouse or keyboard to realize some operations such as translation, rotation. The system better achieved virtual simulation of training and teaching of a type of cylinder cover for the user to save costs and improve work efficiency.