Effects of estuary regulation engineering are related to structure type of its dykes, but it is difficult to study the effect of local complex structure with physical model directly. Taking Nâ...¡C segment of the 2nd phase project of Deep Water Channel at Yangtze Estuary as a case, the paper discussed the method of research on engineering effect of hollow block structure by combining flume experiment with physical model. The method makes it possible to research the effects on current and riverbed induced by complex local structure with large-scale physical model. By comparison of different schemes, it is derived that the scheme without 2600m-long training dike of NIIC segment do harm to the exit channel of North Passage, and there are little influence with the scheme of the height of 2600m-long training dike of NIIC segment debasing 1m or the scheme of adopting hollow-block mound breakwater structure.