Marine geo-hazard factors in the western South Yellow Sea were studied based on seismic profiles. There are different types of factors which may cause geo-hazards in the study area, such as coastal erosion and siltation, submarine shoaling, shallow gases, buried paleo-channels and paleo-delta, sand ridges, steep slope, soil liquefaction, submarine deep scour channel, landslide, faults caused by differential compaction, and so on. The characters and distribution of geo-hazard factors were described and discussed based on the distribution map of main marine hazard factors we compiled.