Abstract: Estuary deltas and coastal cities are facing with the rising risk of the compound flooding due to the coincidence of storm surge,extreme precipitation,high tide and high river discharge. A new integrated numerical modeling system,which coupled atmosphere,ocean and coast processes,was developed to simulate the extreme compound coastal flooding (including four threats of flooding) in Shanghai. The new developed model was calibrated to provide a valid numerical solution for the integrated compound flooding simulation. The results showed that flooding area (inundation depth > 0.2 m) was reduced by approximately 62% after the enhancement of seawall and levee in 1998. Therefore,it is concluded that seawall and levee construction plays a key role in coastal flooding prevention in Shanghai. The accurate simulation of extreme compound coastal flooding provides rational information for the future planning of property insurance and city development.