The topography around the Taiwan Strait has been formed under the control of geological tectonism. However, modern oceanographic factors also play an important role in the developoment of topography and sedimentary structure in the strait. According to the characters of the topography (Fig.2) and its bottom materials (Fig.6)，the strait may basically be divided into two areas along the 24°N boundary line. The southern area is called the Taiwan Shoal, consisted of underwater dunes. Its sediments are composed of coarse to medium sands. To the south of the shoal the inner shelf topography is relatively flat and the outer shelf is rather steep. The sediments of the whole shelf are composed of fine sands, which are considered as relict sediment. The outer slope of the shelf is very steep with an average depth of 143 m. There are some biogenic materials and authigenic minerals in the slope sediments. The northern area of the strait (off the middle Fujian Province) consists of Wuqiu Channel near the shore, submeraged reefs and ridges in the middle and deep valleys in the east. Wuqiu Channel sediments are composed of fine sands?and silty sands, and in the east of channel sediments are clayey silts. The deep valleys might be a sedimentary area of terrigenous, relict sediments and marine sediments. To the further north of the strait the topography is relatively flat and sediments are composed of clays at the coastal area and gradually become fine-sand as relict sediments.