Banqiao sag lies in the middle-northern of Huanghua depression,and Shasan member is the main oil-generating strata and reservoirs in the area.Based on studies of sedimentology characteristics, petrology characteristics and heaven minerals association distribution of sandbodies of Shasan member in Banqiao sag,the result indicated that alluvial fan- fan delta-deep water turbidity fan-deep lake depositional system and beachy subaqueous fan-deep lake depositional system were developed.Different source provenance areas controlled the development of depositional system by controlling the movement of main border faults.During the rifting-subsiding stage of the basin, the north Yanshan fold belt source provenance bypassed Beitang sag and Haihe fault,formed fan delta in Changlu area,and pushed into Banqiao sag to form deep water turbdity fan.From different inlets of the west-north Cangxian uplift,the sediments poured into sag as beachy subaqueous fan or fan delta along Cangdong fault down-dropped block,they would push into sag to form deep water turbidity also.Applied the theory of depositional system distributions and oil-and-gas accumulation,the middle facies belt of depositional system,such as deep water subaqueous fan and fan delta,have good oil-generating strata and reservoirs,they are the most prospective areas for exploration.