Abstract: The main types of temporary support systems in immersed tunnels are described (i.e. three-point support, four-point support, and five-point support) and a comparative analysis is carried out. The five-point support system was applied to the river-crossing tunnel of the East-West Expressway in Saigon, Vietnam, and its design and construction control are introduced in this paper. Research results and practice show that this five-point support system can ensure that the elements are supported by at least three points and guarantee element stability and accuracy under water, especially for a long immersed tunnel with enormous elements.