Abstract: According to the research data in 2007, based on the distribution of grain size and element geochemistry of surface sediments in 212 stations in the southwest of Liaodong Peninsula and the middle of Bohai Sea,ecological risk by heavy metal pollution was assessed and the environmental quality evaluated. R-model and Q-model approaches were adopted to define element geochemical assemblages. The analysis results indicate that the surface sediments element distribution pattern of the investigation region is basically controlled by the grain size and sediment sources. The element composition is similar with other estuarine areas and coastal waters in China. The environmental quality is generally high. The ecological harm of heavy metals is slight. There are three regional geochemical patterns.:the pattern dominted by Al₂O₃, F₂O₃, Na₂O assemblage in the Eastern Laizhou Bay, the pattern dominated by SiO₂ in the east coast off Liaodong Peninsula and mid-Bohai Sea area,and the pattern dominated by CaO, CaCO₃ and heavy metals in the coastal waters of south Dalian.