Many abnormal sedimentary rocks are found in the lower Ganchaigou Formation，Kunbei step-fault zone of the southwestern margin of Qaidam Basin. The vertical sequence of seismites in the study area was researched further and its tectonic significance and importance to oil and gas accumulation were discussed. Through systemic observation and comparison of drilling cores from Well Qie8，Wu8，Yuedong110，Qie6，Hongdi107 and Lü13，symbols indicating the role of ancient earthquakes mainly include synsedimentary micro-fractures，earthquake cracks，liquefied sandstone veins，structures of vibration liquefaction and deformation，seismic turbidites，seismic breccia and collapsed structures. According to the occurring process of earthquake in the study area，the vertical vibration and liquefaction sequence of the seismites from top to bottom is as follows：seismically turbid bed，normal homogenized overlying bed，liquefied sandstone vein bed，seismites breccia bed，vibrational liquefaction deformation structure bed，ladder-shaped faulted bed and shattered rock bed. The discovery of the seismites can provide evidences for the study of ancient earthquakes. Through comparing the structural characteristics of the seismites，the seismic intensity was divided into five grades. Seismites can be used as a symbol of tectonic active period，indicating a strong period of tectonic activities. Seismites can not only be reservoir rock for oil and gas enrichment but also can be the carrier for oil and gas migration，which provides the conditions for hydrocarbon accumulation.