The realistic modeling and rendering of ocean surface is one of hotspot and difficult problems of computer graphic. Most of the recent ocean wave simulation is based on plane and is in a limited region. They didn’t consider the factor of earth curvature and the edge between ocean and land, can’t be used on digital earth flat. In this paper, a new method of GPU-based simulation of large-scope ocean wave is presented. It not only consider the factor of earth curvature, but also the edge between ocean and land, can be used on digital earth. First, ocean wave model considering sphere curvature is presented. The model not only reduces computation obviously, but also resolves the “compress phenomenon” at the high latitude. Then, the visible part of the ocean surface is sampled with screen-subdivision algorithm. Finally, the cost computation of vertexes and color of ocean wave are performed by the programmability of the modern GPU. Results show that the method is efficient and users can fly over ocean surface of digital globe in interactive rates on common PC graphics hardware.