This study addresses excavation efficiency and deformation control challenges in constructing deep, narrow foundation pits within complex urban environments. Taking the Shanghai CDC's new building project as a case study, we implemented an optimized earthwork strategy based on zoned-block and layered excavation principles to enhance spatiotemporal effects. The research specifically analyzed the impact of excavation sequencing and support installation timing on pit deformation. Results demonstrate significant improvements in excavation rates and effective deformation control. Key construction techniques for such constrained sites were formalized, providing practical guidance for similar engineering.