Abstract: The salt lake sedimentary of Paleogene in Zifusi sag developed Shashi formation, Xingouzui formationlower segment source rock. Geological and geochemical analysis shows that: Xingouzui formation lower segment mud interlayer and Ⅱ oil formation has higher organic matter abundance, reach to poor-middle grade, Xingouzui formationlower segment Ⅲ oil formation and Shashi formaiton uppersegment are poor source rock, Shashi formation upper segment, Xingouzui lower segment source rock organic materare mainly Ⅱ2-Ⅲ,Ⅰ,Ⅱ oil formation with lower maturity isin early period, Ⅲ formation enter later mature period.Source rock evaluation shows that Xingouzui lower segmentmud interlayer and Ⅱ oil formation has higher hydrocarbongeneration potential.