Based on cores，outcrop observation and analysis test data,，three types of sediment gravity flows aye identified in the sixth member of Yanchang Formation in the deep water area of lake center in Ordos Basin，including sandy debris flow，classic turbidity current and slump．Sandy debris flow is a new-discovered sandy in the continental petroliferous basin and comes under laminar flow，turbidite formed by turbidity current is turbulent flow，and slump are slumping deformable bodies caused by sliding or slumping in the deep water environment．These three types of gravity flows have essential distinction in the rheological features．In the past，the deposition of turbulent flow was dominant in the research of deep water sedimentation in Yanchang Formation．Three of them are attached in space and transform ed in time．From sandy debris flow to slump，the petroliferous property is weakened，and the A section of classic turbidity is moderate．The further study shows that sandy debris flow is the main contributor for the production in the deep water area of lake center,and its plane distribution controls the accumulation an d high production of the reservoir．