Abstract: The loess. is characterized by the big openings, vertical joints, collapsibility and poor erosion-resistance. In the middle reaches of the Yellow River, the loess distributes widely and thickly, which lead to many problems of environmental engineering geology such as sink holes, gulches, river erosion, landslides, collapse, slumping and so on. These hazards threaten the safety operation of oil and gas pipelines. The analysis on formation mechanism of the loess geology is made and correspondent countermeasures against the loess hazards are proposed in the paper.