Abstract: Lowstand-tract delta sandst one have many favorable advantages in the oil and gas reservoir conditions:good reservoir,close to oil source,close to the fracture system and better reservoir cap configured etc.The Bohai oil field prac-tice in recent years has proved that lowstand-tract delta sandstone is an important area in Bohai subtle reservoir exploration.First of all,this paper discussed the formation conditions of lowstandtract wedge-shaped delta sandstone,then analyzed the profile and surface characteristics of a typical lowstand-tract wedge-shaped delta sandstone in LD4-2 oilfield.Through the forward wedge modeling and case study of several lowstand-tract wedgeshaped delta sandstones,the author discussed the seismic response characteristics of the pinch-out line on lowstand-tract wedge-shaped delta sandstone,and proposed a new concept "Tuning pinch strip".With the application of this technolo-gy,the author effectively portrayed the lithological pinch-line of JX1-2N Stratigraphic trap.At the same time,Tuning pinch strip " concept improved the seismic descrip-tion technologies of subtle traps under less well conditions and also provides a reliable theoretical basis to describe the pinch-line of similar lowstandtract wedge-shaped delta sandstone with strong operability.