Abstract: Subbottom profile, side-scan sonar and precise depth recorder have been used to classify the factors of geo-hazards in the modern Yellow River delta. The analysis result suggests that there are different geo-hazard factors during different periods of development of the Yellow River delta:(1)In the present estuarine area, the submergence of the high silt concentration forms the unique phenomenon of turbidity current in the Yellow River mouth. Because of the rapid sedimentation and un-consolidation of the silt in the estuary, the lobes of the Yellow River delta splinter towards the ocean in the form of slump step.(2)There are a lot of seabed landslides and erosion structures in the north of the abandoned delta lobe, because sediment input of the estuary is in discontinuity and due to the influence of north wind in winter. (3)The situations in Chengbei area are similar to those in Gudong area.After a long-time reworking, various geo-hazards are found in these two areas, especially in the delta slope where water is 5~8 m deep.