Virtual Reality technology is being widely used in various fields, especially in industry. it is widely used in practice for assembly simulation. However, the size of the data for simulation expands quickly along with the increase in components, which make it inconvenient for web publishing but can only be viewed locally. This paper proposes a approach to reduce the size of simulation file using lightweight models and Virtools. Thus the new assembly simulation file can be shared through internet or intranet, and people who have a computer connected to the internet or intranet can view the simulation file easily, and also it is convenient for worker training and operation guide. At Last, an example of assembly simulation in aircraft horizontal tail was given, and the result is proved to be effective.