There have been 29 producing oilfields in the Bohai Bay rim,belonging to three domestic main oil oilfields companies(Liaohe,Dagang,Shengli).The procedure of production is running the risk of crude oil dripping,dropping,leaking,et al.The leaking crude oil caused severe oil contamination in the coastal territory.It is necessary to conduct a thorough renovation.While the sonochemistry has an unique advantage in the realization of separating oil-soil hybrid system,it is considered as one of the most potential technologies to carry out oil-soil homogeneous system decontamination.In this regard,we perform our investigations on local oilsands systems(MOS) to determine physical characteristics of system,the calcium,magnesium,bicarbonate ion concentrations,ultra-fine silica distribution and oil content distribution in contaminated soil.These are the main factors influencing recovery efficiency and purification extent.The results obtained show that the soil of Yellow River estuary region which is contaminated by petroleum is alluvial fine soil,viscosity of detained oil is substantially affected by the temperature with the features of non-Newtonian fluid and a higher pour point,the iron content of soil sample is adequately high,the maximum content of calcium and magnesium cations is 353.3 mg·kg-1 and 690 mg·kg-1 respectively,bicarbonate ion content close to 180 mg·kg-1.According to its specific size and mineralogical properties,the seaside soil can be considered as one of active solids,which can affect the later oil-soil separation.Furthermore,the rich distribution of soil contaminated by oil is close to the surface,especially in 30 cm depth range or so.