Ship lock reconstruction project on the Fuchunjiang River is the first project of high-grade and large-scale ship lock renovated from the old lock on the lower course of the existing and running power station hub.Because the hub reservoir’s capacity is small,we can’t adjust the flood dispatching in combination of the lock construction.Besides,the cofferdam is close to the hub sluice,so the construction will occupy a certain part (in width) of the river,and thus have an impact on the flood discharge and flood control and the strong impact of the flood discharge will threaten the cofferdam and foundation pit,so we need to focus on the research of construction diversion and cofferdam scheme.Based on the comparison of 3 different cofferdam layouts and structural types,we recommend to adopt the overflow earth and rock cofferdam style,which is characterized with easy construction and moderate investment,and can meet the requirements of flood control and construction.