In this paper the authors present a thought of dynamic studies on hydrocarbon migration and accumulation, corresponding methods, as well as an example of application in the Chengbei Fault zone, the Huanghua Depression, the Bohai Bar Basin, China. Based on mass balance analyzing and hydrocarbon loss on pathways estimating, the flux of hydrocarbon in migration pathways may be estimated that permits us to assess quantity of hydrocarbon migrating and accumulating in different directions.