Abstract: The prestack elastic impedence inversion is a method of inversion established on the basis of nonzero offset and,which is an inversion method with abundant information,high resolution and fast calculation speed by utilizing pwave velocity,s-wave velocity and density.This method was applied in He-8 of Sulige area because of its characteristic of ambiguity.So it is of great important to select different incidence angles so as to better distinguish the gas-water contact.Correlation analysis was firstly carried out by using well logging and petrophysical property to solve for the best angle of the elastic impedance,and on this basis to obtain the best angle in the elastic inversion.The result shows that the elastic impedance can not only improve the reservoir indentification but also play a great role in exploratory development of subtle oil-gas reservoirs in Sulige area.