Abstract: The exploration of Kuqa sag shows that the salt layers are closely related to hydrocarbon.Two seismic profiles are analyzed to find out that salt layers,the strata above and below salt seem isolated,but are interactive actually.The salt layers deform on palaeohigh,the strata above salt deform on the wings of salt pillow.The distributing range of salt layers controls the deuteric development of structures in this basin,the propagation of structural deformation ceases where salt layers vanish.The deformation in the area where salt layers develop can be divided into three parts,i.e.deformation in salt layers,deformation above salt layers and deformation below salt layers,which are interconnected but different.The area without salt mostly develops structures that involve basement.Salt layers can delay the thermal evolution of source rocks which are below salt layers and improve reservoir rocks.Salt layers can seal oil and gas reservoir with super pressure and physical property,it is in favor of the preservation of oil and gas below salt layers.Owing to the plastic flow of salt layers,the structural traps below salt layers are conserved after intense tectonic compression.

Key words: salt rock, structural deformation, hydrocarbon accumulation, function, Kuqa sag