The development of Web-based global 3D visual system has made progresses. However, there exist few mature and effective ways for managing, transmitting and visualizing massive spatial data. Based on the related work, the paper illustrates the ellipsoidal quadtree technique for rapid access multi-scale and multiple level geographical data, integrates the streaming with level-of-detail rendering method for transmitting the data on the network, and implements large-scale terrain surface simplification using M-band wavelet transforms and multiresolution triangulations. We fulfil a web-based global terrain visual system using COM components on the basis of the above techniques. The system has a good prospect in the military simulation and city plans.