The finite element analysis method is used to simulate the construction condition of a foundation pit support project in foshan city, and the surface settlement, horizontal displacement of pile body and the change process of inclined bracing axial force during excavation are analyzed, providing reference for the preliminary design of inclined bracing foundation pit support system in deep silt area.The sensitivity of slope and spacing of inclined bracing are analyzed by single factor analysis.The results show that in the deep silt area, the slope bracing has a far-reaching influence on the foundation pit surface settlement.Under the action of inclined bracing, the increment of horizontal displacement of pile top is effectively controlled.The inclined bracing is subjected to pressure in the support system. In this project, the maximum value of the axial force of the inclined bracing appears in the leftmost part of this support section, and the minimum value of the axial force of the inclined bracing is in the middle part of this support section.When the inclination Angle of inclined support increases, the soil mass below the inclined support is closer to the support point, and the uplift curve of the pit bottom shows a significant downward trend.The variation of inclined bracing spacing has little effect on the heave of pit bottom, but the axial force of inclined bracing is obviously affected by it, and the linear increase trend of equal slope between the two is shown.