The excavation width of some deep foundations and underground structures ranges from several to hundreds of meters in engineering. The deformation characteristics of the retaining structures and ground of these deep excavations vary with the excavation width. The two-dimensional finite element method is adopted to investigate the deformation characteristics of retaining structures and ground with different ratio of the excavation depth to the excavation width. The numerical results show that the magnitude of ground settlement and basal heave as well as the magnitude of horizontal displacement of basal all increase nonlinearly with the ratio. The magnitude of horizontal ground surface displacement decreases with the ratio first

then increases. The lateral deformation of the retaining structure varies gradually from introversion-type to extroversion-type as well as overall movement towards the inside excavation with the increase in the ratio.