Abstract: This paper takes the combined soil and rock foundation pit with the adjacent buildings in coastal area as example, uses the structure style of micro steel pile-anchor-soil nail, and studies the deformation of the supporting structure induced by excavation under different constitutive models based on PLAXIS software. It chooses the most appropriate constitutive models to study the deformation law of supporting structure under two key factors, i.e., the prestress coefficient of anchor and the flexural rigidity of micro steel pile. The results indicate that the vertical displacements of ground induced by excavation are similar between HS and HSS models, which are converged with the field measured values. The difference of the horizontal displacements of pile between the theoretical values calculated with MC and MCC constitutive models and the field measured values increases gradually with the development of excavation. The HSS model can describe the deformation law of supporting structure induced by overloading of adjacent buildings and excavation unloading accurately. The maximum value of horizontal displacement of pile appears on the ground surface with different prestress coefficient and flexural rigidity of micro steel pile respectively. The prestress coefficient has a significant effect on the control of horizontal displacement at the ground surface and the anchor. It's reasonable to determine the range of the prestress coefficient when the horizontal displacement at the place of the first anchor is zero. Then, the objective value can be chosen in the range of prestress coefficient according the deformation requirements of surrounding environment. Finally, the flexural rigidity of micro steel pile can be determined according to the objective value of prestress coefficient, which leads to the anchor and micro steel pile being made up of supporting system of deformation coordination.