Abstract: For the characteristics of deep foundation pit support in soft soil area,based on engineering examples,this paper introduced the emphasis and difficulty of large area and irregular deep excavation support,and numerical simulation software is used to analyze the influence of excavation on surrounding environment.The results indicated that:for large area and irregular deep excavation engineering,it is very important to control the deformation of foundation pit by using the principle of "time-space effect" to excavate zonally and rational arrangement of support system.It has important reference value for similar excavation engineering.