Adjacent foundation pit engineering in dense urban areas is easy to cause deformation， structural cracking， and water leakage of shield tunnels with super-large diameters （>15m）. At present， the construction of super-large diameter shield tunnels is in the initial stage， the deformation response law of tunnels under the influence of foundation pits is unclear， and there is a lack of reasonable influence zoning. In this paper， a three-dimensional finite element model of the excavation of the side foundation pit of the super-large diameter tunnel is established by using finite element software. The structural deformation response mechanism of the super-large diameter tunnel is analyzed， and the influence laws of factors such as tunnel buried depth， tunnel-foundation pit spacing， and foundation pit excavation depth are discussed. It is found that "bulge belly" horizontal displacement and "spoon" vertical displacement towards the foundation pit are caused by the excavation of the foundation pit. Compared with the small-diameter shield tunnel， the large-diameter shield tunnel presents a weaker longitudinal deformation and more significant transverse deformation. The tunnel deformation decreases with the increase of tunnel-retaining wall distance， increases first， then decreases with the burial depth， and increases with the excavation depth. After normalization by the excavation depth， the maximum tunnel deformation and distance can be fitted well by an exponential function. A normalized influenced zone was proposed， which provides an important reference for the protection of the large-diameter shield tunnels in engineering practice.