The studies on sequence stratigraphy of Tertiary and upper Cretaceous and sedimentary features in Dainan Formation in Gaoyou Sag, North Jiangsu Basin indicated that there were multi-level and multi-style slope-break belts in faulted lacustrine basins. These slope-break belts controlled the development of sequences, depositional systems and the distribution of sand bodies in Dainan Formation. The Z-1 fault in Gaoyou Sag was a steep-slope boundary fault, which controlled the development of coarse-grained fan depositional systems. The Z-2 fault was a steep-slope internal fault, which controlled sand bodies thickening zones of fan depositional sys- tems. Hanliu Fault was a gentle slope internal fault, which controlled the sand bodies thickening zones of delta front and the develop- ment of slumped turbitide fans, and also controlled the development of low stand system tracts and delta front-shoreline of high stand systems. The development of slope-break behs was controlled by periodic tectonic activity of the basin. The multi-style subtle traps de- veloped mainly near the internal faults, where the key promising oil and gas exploration activities were concentrated.