Because of the slow network transmission speed and the large amount of data of the virtual exhibition system scene file on web environment, exhibition scene takes a long time to load for the first time, and it has standstill and models flashing during scene roaming. To solve these problems, this paper proposed new methods, which are Gradually Optimize Two Level of Detail and model-mapping transition display optimization technology. GOTLOD technology loads the scene file by splitting scenes and asynchronously, it uses low accuracy of the model show to build scene quickly, and it uses stadia and dynamic to switch different precision of the model. Model-mapping transition display optimization technology uses the difference size of Stadia to switch between models and textures. Experimental results shows that the initial load time reduces 71% and FPS of scene roaming value increase 3.9 times by using the GOTLOD and model-mapping transition display optimization technology. The optimization technology reduces the scene loading time effectively, and solves the high-fidelity runtime scene roaming fluency problems.