Abstract: In order to improve construction quality of immersed tunnel in urban river, the construction characteristics of the immersed tube tunnel built and under construction in Guangzhou are studied, and four construction characteristics are summarized as follows: (1) difficult tunnel layout due to the limited connection between the road network on both sides; (2) complex surrounding environment, high requirements for tunnel construction landscape and environment protection; (3) the narrow Pearl River Channel, high embankment flood control requirements and large associated engineering; (4) the difficult foundation trench excavation and foundation setting owing to the shallow burial bedrock and great rock surface undulation. Then，combined with the construction practice of Zhoutouzui tunnel, Chebeinan tunnel, Ruyifang tunnel, and Exhibition West tunnel in Guangzhou, the innovative concepts of sharing, integration and environmental protection are systematically elucidated, and the innovative technologies including the variable section element, shared dry dock, mold bag sand cofferdam on hard foundation, environmental vibration control of underwater foundation trench blasting excavation, and full section pouring in dry dock are summarized. Finally, the future research of immersed tunnel construction in central urban area is prospected to focus on the aspects such as the overall design scheme  integrating immersed tunnel and urban underground space, the prefabrication technology in mobile dry dock, the element floating pouring technology without dry dock, the environmental protection and efficient excavation method for the rock foundation groove under sensitive urban environment，and application of new material and novel structure for pipes.

Key words: immersed tunnel, Guangzhou central urban area, shared dry dock, mold bag sand cofferdam on hard foundation, variable section element; environmental vibration control