This paper introduces the design of deep buried spread foundation with braced excavation system for the South Anchorage of the Fourth Nanjing Yangtze River Bridge. The braced excavation system applied can be described as shaft diaphragm wall foundation with the plane section of "∞" shape including two 1.5 m-thick 59 m-diameter semi-circle and one 1.5 thick separation wall, and total length of 82 m and width of 59 m. However the separation wall provides the support for two semi-circles, it will not separate the bottom plate of foundation as the bottom elevation of wall is constructed in a higher level; and the separation wall is to be removed slightly in order to construct the top plate as a whole. The form of "∞" shape is superior than that of circle and rectangular by smaller plane area, larger cross sectional moment of inertia, smaller radius, smaller circumferential stress of diaphragm wall and better safety and feasibility, which great reduces the total costs and improved the construction safety.