Interactive downloading huge virtual scenes on Internet is always a challenging task of large scale DVE(Distributed Virtual Environment) systems. Along classical progressive transmission mechanism based on AOI (Area of Interest), this paper proposes a new concept SMLAOI (Scalable Multi-Layer AOI). Then, presents an integer incremental SMLAOI culling algorithm without multiplication, divisions and floating calculations, which allows the WebVR regions nearer to current viewpoint to download with higher delivery priority, and reduces time that a user need to wait for initial scenes. Finally a framework of progressive downloading large scale WebVR scenes based C/S is designed.