Abstract: As rich media applications often appear on the mobile devices, there is a high demand to the rich media engine. To promote engine performance, we present a rendering optimization strategy to rich media scene on mobile devices. The strategy includes the optimization on partial rendering and polygon fill. The partial rendering is achieved through tracing the invalid area along with scene change. On the polygon fill aspect, we put forward a kind of Grid algorithm, to record the intersection information of the polygon edges and the scanlines to proceed antialiasing and polygon rasterization fill, including the complex self-intersecting polygons. The algorithm proves much better than the traditional edge list fill and scan line seed fill methods in the time and spatial complexity, and more suitable for the mobile devices. Final simulation tests show that good results in optimization can be achieved by the strategy.