Abstract: In recenty ears,more and more attention is paid on hydrocarbon accumulation research of Triassic Yanchang formation in Ordos basin and important progress has been made.Nevertheless, geochronology of Mesozoic reservoirs in this area was rarely studied in the past years.Geochronology of the Triassic Chang 2 and Chang 6 oil-bearing Formation in eastern North Shaanxi slope which is studied through organic inclusion analysis method with analysis of hydrocarbon generating history in this paper. The study shows that or ganic inclusion characteristics of the Triassic Chang 2 and Chang 6 oil-bearing Formation in eastern North Shaanxi Slope are very similar.The homogeneous temperature of the inclusions is 90-120℃.It shows that the forming times of hydrocarbon accumulation of the Triassic Chang 2 and Chang 6 oil-bearing Formation in eastern North shaanxi slope are very close.On the basis of analysis of burial history and thermal evolution history,the age of accumulation is nearly the late Early Cretaceous.