Considering the averaged river discharge and wind in dry season, the impacts of reclamation project of Nanhui tidal flat on the currents and saltwater intrusion were numerically calculated and dynamically analyzed. The funnel shape was reduced, flood current and tidal prism in the South Passage were changed after the reclamation project. The reclamation project resulted in tidal prism in the South Passage reducing 13% in spring tide and 16% in neap tide, and the flood currents spilling over the dikes of the deep water channel decreased; The northward salt fluxes spilling over the dykes from the South Passage were weakened which made the seaward salt flux in the North Passage reduced, the landward salt flux decreased the upper and middle reaches of the South Passage and on the southeast side of the project, whereas was increased at the mouth of the South Passage. After the reclamation project, the salinity front in the South Passage was weakened, the salinity in spring tide increases with exceeding 1.0 in the area near the mouth of the South passage and on the southeast side of the project; the salinity decreased with greater than 0.5 at the upper and middle reaches of the South Passage, in the North Passage and in the Hengsha eastern beach due to the decreases of the tidal prism, current spilling over the dikes and landward salt flux. The salinity in neap tide decreased in the whole South passage with greater than 1.5 because of the decreases of the flood current and salt flux at the mouth caused by the weaker tide. The net water diversion ratios were reduced slightly in spring and neap tide in the North Channel, increased 1.57% in spring tide and 1.50% in neap tide in the South Passage because the salinity front in the South Passage was weakened after the reclamation project, which weakened the block effect of the river water into the South Channel. 