China is currently at an important stage of urbanization. In recent years, the number and scale of under-lake tunnels in southern cities of China are growing consistently, which brings opportunities and challenges in intelligent construction and operation maintenance. Due to the long length of the under-lake tunnel, the large volume of concrete to be cast, the complex environment of the buried section and the underground environment of the lake bottom, the hydration heat and stress crack have been the main challenges of the under-lake tunnel engineering in crack control and waterproofing aspect. Simultaneously, with the development of big data, intelligent construction, information technology, and other techniques, these techniques are gradually applied to the whole life cycle of tunnel engineering including survey, design, construction, operation, and maintenance. The construction of the lake tunnel project is setting off a new round of technological innovation. This paper systematically summarizes the technical breakthroughs and application of technologies such as intelligent construction and information technology in the construction of under-lake tunnels in China, and puts forward reasonable suggestions on the key technologies of intelligent construction and operation maintenance for urban under-lake tunnel engineering.