Abstract: Jurassic strata are an important petroleum bearing sequences in Qaidam basin. In recent years,exploration activities have been made with new discoveries. Based on the analysis of origin and conditions of Jurassic reservoir in Qaidam basin, it is pointed out that it is a primary reservoir,while Teriary reservoir is a secondary one formed from crude oil remigration through the fault, and it is necessary to conduct regional exploration and comprehensive studies in order to determine the source sag. Based on this, the guiding principle of determining sags for reservoir delineation should be performed. According to the preliminary analysis, there existed good conditions for hydrocarbon generation in Yiliping sag of Yiliping depression. Hence, beside the known crude-bearing zones,Eboliang anticline may be another petroleum accumulation zone, but Yikeyawuru anticlinal belt should be paid attention to.

Key words: Qaidam basin, Jurassic, primary reservoir, continental deposit, marine deposit, remigration