Abstract: Based on the comparative study between outcrop and well logging data, the sedimentary facies of Ziniquanzi formation are divided into alluvial fan, braided river, braided river delta and lake ones. According to the two suits of mud which developed stably in Ziniquanzi formation, unconformity, erosion surface or sedimentary system interface in study area, the Ziniquanzi formation in fault-fold zone in southern margin of Jungar basin is classified into two segments, the upper segment and the lower segment. The diagram of the sedimentary system distribution is worked out by the two segments. The results show that the early Ziniquanzi formation (the lower segment) is in the sedimentary framework of fluvial fan-braded river-braded delta-lake facies; the late Ziniquanzi formation (the upper segment) is in the sedimentary assemblage of braded river-braded delta-lake facies, dominated by lake deposit.

Key words: the southern margin of Junggar basin, Ziniquanzi formation, sedimentary facies, sedimentary evolution