Based on drilling and seismic data,the Paleogene developed in Liaodong Bay can be divided into five third-order sequences bounded by six sequence boundaries.Through analyzing depositional systems in each sequence in detail,the Es-3 time was defined as fast rifting.During the deposition of the Es-3 member,the lake basin was continuous along the N-S direction but compartmentalized along the E-W direction by several N-S trending faults.Deposition was dominated by steep slope fans and fan deltas.The time of Es-2 and Es-1 was stable settling.The lake basin expanded substantially.The fan delta system and braided fluvial system were developed.Carbonate and clastic deposits were formed on the Liaoxi (west Liaohe) Rise.The time of Ed-3 time was again fast rifting.During this time,shale was deposited.In the time of Es-2,tectonic movement weakened.The basin was higher in the west and north,and lower in the east and south.A series of delta depositionai systems were developed and smallscale slumping turbidite fans were present in semi-deep lake to deep lake.In the time of Ed-1,tectonic movement stopped.Flood plain deposition occurred.Finally the paper presents the characteristics of evolution and distribution of depositional systems both vertically and horizontally.