Shield technology is developing towards superlarge diameter, superlong boring distance and superthick overburden, so as to meet the growing need of rivercrossing and seacrossing tunnel construction. Qiongzhou Strait Tunnel has such features as superthick overburden, superhigh water pressure, superlarge crosssection, superlong distance and complex geology conditions. In the paper, the development of superlarge diameter shield technology under thick overburden at home and abroad is presented, the challenges of Qiongzhou Strait Tunnel, including the design and manufacture of superlargediameter shield machine, the superlong boring distance, the sealing technology under superhigh water pressure and underwater docking technology, are expounded, and outlook is made on such new technologies as the design and system integration of superlargediameter shield, highefficiency rock breaking technology, optimal design of cutter head and cutting tools, the sealing technology, cutter replacement technology under atmospheric pressure and underground docking technology.