Abstract: Recently the dynamics system for pool-foming had become the central issue in the study of reservoir forming and was paid great attention.Based on the review, the author made an intensive study on the dynamic systems for pool-forming in Chezhen Sag.Chezhen Sag can be divided into three kinds of dynamic sub-systems for pool-forming and three sorts of link systems.The dynamic sub-systems consist of heterogeneous & open type on the top, the self-sourced & closed type in the middle and the heterogeneous & open type at the bottom.On the ground of describing the static elements of petroleum system (source rock, reservoir, seal and overburden) and the analyzing the dynamic process (trap formation and generation, migration, accumulation and preservation of hydrocarbon), combining oil-source correlation and oil-gas pool-forming period, the late Guantao-Ming huazhen stagis the key moment of petroleum system.