Abstract: The Qaidam Basin is an inland basin in the northeastern Tibetan PlateauIt has developed thick MesozoicCenozoic sedimentary strataThese strata recorded the evolution of the structure and environment of the basin and its surrounding mountainsBased on Late Cenozoic sedimentary rock magnetic study of the Honggouzi section in the northwest Qaidam Basin，we found that the value of magnetic susceptibility increased dramatically in the～9.8 Ma，together with significant increase the amount of magnetiteCombined with sedimentary facies，lithology and sedimentation rate，and based on the relationship between the magnetic properties of sediments and environmental change，and the tectonic activities，we believe that the dramatic changes of rock magnetic characteristics may have been caused by the changes of sedimentary provenances in～9.8 MaIt may imply a significant uplift event of the northeastern margin of Tibet PlateauAltyn Tagh was one of sources of the Qaidam Basin，which responded to this tectonic movementThe mountin reached certain height so that the erosion rate increased，this process was recorded by Honggouzi.