The topography data of the Zengmu Shoal and its adjacent area are acquired by the SeaBat-8111 multibeam system.The full survey covering over the Zengmu Shoal area gives us new knowledge about the area. It is a flat underwater plat-form consisting of coral reefs, its fathom line is like a trap in near SN direction and its shape is like an isosceles trianglewith the acute angle pointing to the north. The east and west sides of the shoal are steep while its south side is more gen-tle. As viewed from geological evolution, the Zengmu Shoal is a typical biologic coral landform caused by tectonic uplift.