Abstract: A new method for excavation of soft soil deep foundation pit is introduced, that is the excavation method for deep foundation pit based on the vacuum water proof curtain and atmospheric pressure support. This method combines soft soil foundation treatment with excavation of foundation pit effectively, which has advantages such as vertical excavation, no inner support, dry operation, time-saving and cost-saving. The theoretical foundation of this technology is the negative pressure ball stress of vacuum preloading and the barrier function of rigid structure to the lateral earth pressure. In other words, the atmospheric pressure acting on the side wall of foundation pit and the barrier function of rigid structure to its lateral soils are used to replace the traditional support for foundation pit. At the same time, the vacuum preloading also has the effects of precipitation and ground foundation treatment. Engineering example shows the new construction method is feasibe and practical, and it provides a new design concept and direction for the development of pit engineering technology of deep foundation.