Abstract: The Northern-Jiangsu-southern-Yellow-Sea basin is located in the lower Yangtze block, its tectonic evolution is complicated, and its tectonic boundary and characteristic is still controversial.Regional tectonic characteristic and tectonic evolution have significant influence on regional seismic activity today. Through analysis on regional geological and tectonic evolution, we consider that the tectonic evolution of lower Yangtze block is independent of Yangtze block.This paper presents the boundary of the basin, describes basic regional tectonic characteristic and processes of tectonic events that has significant influence on seismictectonic nowadays, and mainly discusses the formation and evolution characteristics of NW-trending tectonics in this region and its significance to moderate and strong earthquakes.