Disturbed soil is widely spreaded on the subaqueous delta of the Yellow River. It is different from the ambient undisturbed soil in many aspects. A sea area in the old Yellow River estuary is chosen as the study area. Geotechnical drilling and geophysical prospecting is processed to get the stratification and the geotechnical characteristics of the soil in this area. It turns out that compared with the undisturbed soil

the bulk density of disturbed is bigger

the void ratio is smaller

the water content is lower

and the shear resistence is higher. The limit liquefaction depth is calculated. The depth is coincident with the maximum thickness of the disturbed soil; and according to the statistics of the geotechnical factors

the abnormity of the soil is more or less limited in this very depth. The forming mechanism of the disturbed soil is discussed; and liquefaction during storm time is believed to be the controlling factor.