The Middle and Upper Ordovician is one of the main target zones of oil and gas in the Tazhong area (central Tarim Basin). On the basis of synthetic stratigraphic subdivision and subcorrelation, this paper has analysed the distribution of different sedimentary facies. The platform marginal facies is mainly composed of reef, shoal and slope deposits, and these facies were developed in different evolution stages of the carbonate platform and have constituted important oil and gas reservoirs in the research area. These facies have a relatively larger thickness and are mainly distributed in the No.1 faulting zone, the TZ10 structural zone and the southern edge faulting zone of the Tazhong area. It is concluded that in the Tazhong area, the synsedimentary structures in the Middle and Upper Ordovician had an important influence on the formation of these platform marginal facies. Through interpretation of a large amount of 2-D and 3-D seismic data, we have found that three widely developed seismic facies, including mound-like facies, sphenoid foreset facies and desultory reflection facies, are also mainly distributed along the major structural zones. Compared with those well-identified sedimentary facies, these seismic facies are regarded to be the platform marginal facies. In this way, the accurate positions of the marginal facies can be figured out through processing of a large amount of seismic data.