The invention relates to the track traffic and tunnel category, in specific to a super-deep foundation pit construction method for high pressure water areas. The method adopts underground continuous walls (or drilling piles, drill biting piles and corresponding waterproof curtains) as enclosure structures and inner supports as support structures; in the premises of complying with pressure water safety factor required in specifications, performing open excavation down to a certain elevation; during the course of open excavation method, carrying out casting for surrounding purlins, supports andupper side walls; then, adding water into the foundation pit, and the water injection height can guarantee the excavation to the bottom can resist pressure water and meet certain safety factors; performing underwater excavation down to the baseplate elevation and overbreak a certain depth for underwater bottom closing concrete cast; then, pumping water out of the foundation pit before casting baseplate and back-casting remaining internal structures.