To the combined support system of soil nailing and pile-anchor for deep excavation, by the numerical calculation with FLAC3D software, the analysis is made on the influence of excavating process to displacement, stress and stability safety factor of support system structures, as well as the laws of ground deformation caused by excavation. 2 retaining schemes are considered; one is the retaining structure composted by 2 layer soil nails and 1 pile-anchor, the other one is the retaining structure composted by 4 layer soil nails and 3 pile-anchors. Based on the calculation results, comparative study is carried out on the support effects of different schemes to analyze the feasibility of the support scheme. The paper presents the comparison of support effects between the adopted scheme in the engineering and field measured results.