When the construction period of a project is pressing, the land formation and soft foundation of this project is considered constructed before the wharf structure, the chosen of the position of the temporary cofferdam is the key of the design. The conclusion is drawn from a project analysis in Zhuhai that the position of the temporary cofferdam must be determined under the consideration of the geology and the wharf structure follow-up and the range of the soft foundation. It must be adaptable to the possible wharf structure, to reduce repeated construction and foundation treatment as much as possible.