Abstract: During the excavation of foundation pit in rheological soil layer,the phenomena of over-excavation and support setting not timely occur frequently,and the characteristics of soft-soil creep,the deformation of retaining structures is increase sharply. With the secondary development program of the elastic-viscose-plastic constructive model,simulate the conditions of normal construction and over-excavation of foundation pit in Soft clay area,analyze the time change regulation of retaining structures and safety state of foundation pit,in order to achieve effective control of the deformation and protect the buildings adjacent to foundation pit.