In this study, the recent change in the Yangtze Estuary is described using the results of the reclamation project of Hengsha Shoal. A 2D numerical model of tidal currents for the estuary is established. Some changes in the tidal capacities, the peak velocities of flood, and the ebb currents in the North Channel and the North Passage were found after land-forming projects at Hengsha East Shoal (HES). The diversion ratio of the upper section in the North Channel decreased by 0.49%, while that of the lower section in the North Passage decreased by 0.09%. The high tide level in the North Channel lowered by 5–15 cm in some regions, and the high tide level in the North Passage slightly increased by 6–15 cm. The effects of land forming at HES on the flow field mainly concentrate on the North Channel and the North Passage, and the effect on the North Channel is larger than that on the North Passage and less on other reaches.