Research conclusions: The construction scheme of the foundation pit for integrated transport hub should be determined in accordance with the overall thoughts．The construction scheme and the relative parameters should be chosen with numerical simulation and calculations．As there is no criterion for determining the parameters for the exterior—protected construction for the multi—step foundation pit，80 the parameters for the exterior—protected for such foundation pit should be determined in accordance with the ratio of unloaded width(B)and foundation pit depth(H)，the construction method and dewatering condition．For arranging the large—space bracing system and determining its parameters，the concept and principle of equivalent stiffness and even stiffness should be followed and the influence factom of the change of environment temperature，heave and settlement of the bracing column and construction loads should be considered．