Abstract: The author discusses the role of crustal stress and its significance in petroleum geology from four aspects:crustal stress and the formation and evolution of oil-bearing basins,crustal stress and the structures of the basins,crustal stress and the migration of oil and gas,and crustal stress and the oil development.A systematic exposition of the study situation of the crustal stress is made.The magnitude and direction of present crustal stress can be obtained by stress measurement and focal mechanism solution.The magnitude and direction of fossil crustal stress can be determined only by the analysis of structure deformations and microfabrics.