[Objective] Fractured strata during deep foundation pit excavation can easily lead to instability in the surrounding soil. To investigate the deformation response patterns of nearby subway stations during deep foundation pit excavation in fractured strata, this study examines a deep excavation project in fractured strata near Shenzhen Metro Line 5. [Methods] We conducted an in-depth investigation into the deformation of nearby subway stations caused by unloading during foundation pit excavation, employing theoretical analysis, numerical simulation, and field monitoring. Mindlin solution was employed to calculate additional stresses. Based on the stress release method, assuming full or partial stress release in the surrounding and pit-bottom soils caused by excavation, we comprehensively considered the support effect of the excavation retaining structure. Stresses were multiplied by a reduction factor to derive equivalent released stresses for the sidewalls. A theoretical formula for station deformation calculation was established, revealing its deformation mechanism. Three-dimensional modeling analysis was conducted through numerical simulation. Grey relational analysis was employed to perform sensitivity analysis on factors influencing station deformation, determining the sensitivity of each factor to station deformation. [Results] According to numerical calculation results, the maximum settlement deformation of the main structure of the subway station during each construction process was approximately 2.5 mm, and the maximum horizontal deformation was approximately 4.5 mm. Excavation unloaded the soil adjacent to the station structure, inducing horizontal displacement toward the pit center. Numerical simulations indicated that significant longitudinal deformation occurred primarily near the excavation zone, while structures farther away exhibited negligible deformation. Vertical deformation followed a pattern of greater displacement at the top and smaller displacement at the bottom. Comparative analysis between measured data from the central excavation zone and theoretical calculations/numerical simulations yielded the following station horizontal displacement results: Compared to monitoring curves, numerical simulation results were approximately 6% smaller; compared to theoretical calculation curves, numerical simulation results were approximately 8% larger. [Conclusion] Comparative analysis demonstrates that numerical analysis methods provide a reliable basis for subsequent factor impact assessments. Simplified calculations omitted factors such as peripheral loading around the excavation pit and delayed support construction, resulting in monitoring values exceeding both numerical and theoretical calculations. Therefore, construction must strictly adhere to avoiding peripheral loading and promptly installing supports to minimize impacts on station deformation. Sensitivity analysis of factors affecting station deformation using grey relational analysis reveals high correlations with diaphragm wall moment of inertia (0.874), overburden thickness (0.816), and excavation depth (0.759). Among these, diaphragm wall moment of inertia warrants particular control emphasis. During excavation, factors such as economy and safety must be comprehensively considered. Selecting a reasonable structural stiffness can achieve good deformation control, but beyond a certain threshold, this control effect diminishes significantly. The horizontal displacement of the station decreases as the moment of inertia of the diaphragm wall increases, the excavation depth decreases, and the overburden thickness increases, exhibiting a nonlinear relationship. Grey relational analysis identifies that diaphragm wall moment of inertia is the major influencing factor.