Based on experimental and observed terrain data, we analyze the effect of dredged channel on current and river regime in the North Passage of the Yangtze Estuary. The results show that: 1) The current velocity in the main channel increases significantly after the channel depth is dredged to 12.5 m; 2) When calculating the current velocity caused by dredged channel in the north passage, Le Peijiu’s formula is more appropriate; 3) Digging of the dredged channel for 12.5 m intensifies the change of river regime in the north passage, which is one of the main reasons of the change of river regime in the North Passage since 2009. The effect of dredged channel should be considered sufficiently in the analysis and evaluation of the regulation effect of the Yangtze Estuary Deepwater Channel Regulation Project and other relevant waterway regulation engineering.