Ten vibrocores obtained from the outer continental shelf of the East China Sea were measured for their magnetic properties, grain size, Cl- concentration and clay mineral. Results show that the sub-bottom strata at the brim of Yangtze shoal consists of two layers：(1) The upper layer is the mixture of sand and mud with a large quantity of shell fragments, which is characterized by high values of magnetic capacity (x) and saturation isothermal remanent magnetization (SIRM). Magnetite(Fe3O4) is enriched in the layer of sand and mud mixture, representing the strong reworking and deposition in situ by the post-glacial transgression. Iron sulphides found at the sea bottom indicate the secondary transformation of the magnetic minerals in the reduction shallow sea. (2) The lower layer contains the hard and compact yellowish brown clayey silt and silty clay (stiff mud) with a generally faint magnetic property. But extremely high values of SIRM/χ and coercivity (Bc and Bcr) appear locally in the lower layer, evidencing the occurrence of greigite. The concentrated chlorite and Cl- of the greigite bearing sediment shows the stiff mud is the efflorescent result of the early transgression sediment in the subsequent relatively dry climate during the last ice age.