Using the biomarker parameters of n-alkane, the carbon isotope of full oil and the distribution pattern of single molecule, combined with the composition and carbon isotopic characteristics of natural gas, this paper discussed the oil and gas origin and genesis in Dongping area, Qaidam Basin. The results show that the n-alkane odd and even carbon number predominance of condensate oil in Dongping 1 well is equivalent （CPI =1.021, OEP =1.004）, showing the characteristic of high-mature crude oil. The Pr/Ph is 3.06, showing the pristane advantage. The carbon isotope of condensate oil（-31.25‰） is close to the carbon isotope of the Jurassic limnetic facies crude oil in the northern margin of Qaidam Basin, and the distribution characteristics of single molecule carbon isotope demonstrate the organic biological source of terrigenous higher plants. It is considered that the oil and gas in Dongping area are from Jurassic hydrocarbon source rocks, and the natural gas is a typical coal-type gas.