Abstract: We analyzed grain-size compositions of terrigenous fractions in 8 core sediments from the southern Yangtze River mouth and Zhoushan Islands area, and compared the grain-size characteristics between them by using the calculated grain-size parameters. The grain-size compositions and parameters of most of the core sediments from different sites and environments show very clear comparability, except for a core (ZSC07) from the inner part of the Zhoushan Islands. Further more, by using plots of mean grain size vs. sorting coefficient and grain size vs. standard deviation, we can easily know that the fine-grained terrigenous fractions in the core sediments all originate from the Yangtze River discharge. In the inner part of Zhoushan Islands, because of special hydrodynamic conditions and sedimentation processes in the strait channels, there developed very different sedimentation patterns with distinguished grain-size compositions and parameters. At last, we think that the grain-size composition data could be used to directly determine the sediment origins of different sedimentation environments but of the same sediment provenance.