Taking the sandy beach-bar deposit in the 3rd member of Funing formation（Ef

3

） in the "west slope zone of Qintong sag as the research object

based on core

logging and various analysis test data

the sedimentary characteristics and sedimentary dynamic conditions of the sandy beach-bar are analyzed comprehensively

the genetic types of sandy beach-bar have been divided and the main controlling factors under spatiotemporal conditions have been summarized.The research suggests that the sandy beach-bar deposits can be further divided into beach sand

and bar sand

and they have great differences in lithology

color

thickness

particle size and sedimentary structure.According to the analysis of the sedimentary dynamic conditions for the formation of sandy beach-bar

the sedimentary genetic types of sandy beach-bar in the western slope belt can be divided into two types:①the redeposited sandy beach-bar in front or side margin of far source delta

②near-shore sandy beach-bar controlled by near-source alluvial fan.The former is found in each sand group of Ef

3

and most widely distributed in Ef

3

4

sand group.The latter is only found in Ef

3

4

sand group

which is restricted to the southeast coast of the " west slope and developed in belts.The study of sedimentary characteristics of sandy beach-bar in continental faulted lacustrine basin is of theoretical significance for the exploration and development of lithologic oil and gas reservoirs in thin interbedded lacustrine facies.