Loess deposits are widely distributed over the islands in the Bohai Gulf and neighboring regions of northern China. The study region is located in the central of The Miaodao Group islands. Samples from the Dakoubei loess section in Tuoji islands,Shandong Province were employed here for the grain - size and sedimentary analyses. Results indicate: ( 1) the loess grain size distribution of the section is dominated mainly by silt,and the contents of fine clay are lower and sand is higher. ( 2) According to Sahu's discrimination formula and the characters of both the grain size composition and distribution curves,it is found that the main sedimentary deposits are formed in Aeolian environment. ( 3) The section is divided into modern soil layer,two loess layers and paleosol layers,they record the information of climatic change and sea level variations in Bohai Gulf.