Abstract: Nearly N-S-trending structures are found in all basins of west-central China. They are not large in scale but have a marked controlling effect on the formation of hydrocarbon accumulations. On the basis of the research results of relevant subjects, combined with a wealth of drilling, geophysical, experimental and analytical data, and through studies of structural features, sedimentary response to tectonic movement and response to the subsurface paleotemperature field and magnetic fabric analysis, the paper systematically elucidates the features of the Cenozoic tectonic stress field in the Qaidam basin and discusses the dynamic mechanism of the formation of nearly N-S-trending structures and their prominent position and role in the formation of hydrocarbon accumulations in the Qaidam basin.