Abstract: The characteristic indexes of stable heavy minerals can well reflect the provenance informations of sediments. The clastic sediments are collected from the rivers flowing into sea and sea areas in Haizhou Bay of Lianyungang City to analyze the mineral compositions and characteristics of offshore clastic sediments. The light minerals in the offshore sediments are mainly composed of quartz and feldspar, while the heavy minerals consist of zircon, ilmenite, epidote, hornblende, sphene and garnet. The analysis of heavy mineral characteristic indexes shows that the offshore seasand sediments are the products of estuarine-neritic environment, with the placers mainly from the granite, gneiss and eclogite of Lianyungang area, belonging to the littoral sedimentary type of river-sea interaction.