Due to the limited network bandwidth and the fact that the 3D animation data are very huge, it will take a long time to transmit the data of 3D animation through network on one time. As a result, it can't be smoothly displayed in real-time as the transmitted 3D animation data are incomplete. The key technology of WebGL based 3D animation is presented, such as model files preload and transmission of compressed files, et al. Under the condition of limited bandwidth, the proposed approach has the capability to transmit 3D animation content to the client in real time. The 3D model is created and rendered by WebGL, and users can view and interact with the 3D digital animation in high-speed through the browser.