Overpressure is widely developed in the Cenozoic formation of the Youquanzi Oilfield in western Qaidam Basin,and the identification of overpressure genesis has great significance for the study of oil-gas migration and reservoir formation.The measured pressures,logging curves,acoustic velocity-density cross plot,overpressure genesis comprehensive analysis method and overpressure compartment mode for the Youquanzi Oilfield were compre-hensively analyzed.The results show that the negative pressure,normal pressure,overpressure and strong overpres-sure systems were longitudinally developed in the Cenozoic Formation of the Youquanzi Oilfield;the pressure coeffi-cient of the overpressure system was generally greater than 1.3,and the pressure coefficient of some overpressure points was greater than 1.73,showing the characteristics of strong overpressure;overpressure in this area,the main controlling factors were the uneven compaction,tectonic extrusion and hydrocarbon generation;the oil-gas migra-tion was in line with the overpressure compartment mode;the oil and gas were migrated to the Nanyi Mountain Area due to overpressure.The study result clarifies the oil-gas migration direction of the Yauquanzi Oilfield and is of guiding significance to the study of oil and gas reservoirs in western Qaidam Basin and similar regions.