Abstract: Support of prefabricated prestressed fish-bellied beam based on the prestressing principle is a new advanced environmental friendly internal support structure system of deep foundation pit. Two application examples of this steel structure support system in deep foundation pit in soft soil are introduced, including pit enclosure schemes and excavation results. The advantages of this support technology are summarized, including environmental friendliness, economical efficiency, short construction period, with comprehensive benefits. The problems of this support structure in deep soft soil are also discussed. Reference for the similar engineering design and construction in the local area are provided.