Fluid analysis of petroliferous basins includes the present-day fluid analysis and the paleo-flu-id analysis. Present-day fluid characters are closely related to petroleum occurrence. They are also the fundamentals for paleo-fluid analysis. Paleo-fluid analysis consists of the study of the fluid migration history, identification of oil and gas migration periods and directions, and prediction of petroleum resources. Both the present-day fluid analysis and the paleo-fluid analysis consider different space scales. Fluid analysis on different time scales and space scales constitutes then the methodological system of fluid analysis in petroliferous basins. The principle of fluid dynamic system analysis is the most important content in the methodological system. The discussion is then focused on this principle and its application prospects. Several important research subjects, such as dynamic analysis of different types of fluid dynamic systems, mechanism of formation and prediction of abnormal pressure, for which studies should be enhanced, are briefly discussed.