In the overall structure of a shield tunnel, the joint of the pipe segments is the weakest part of the waterproofing system, and its waterproofing performance directly influences the stability and service life of the entire tunnel. With continuous innovation and changes in structural design and construction methods, the occurrence of water leakage or sealing gasket damage at the joints of pipe segments has become increasingly severe. Therefore, research and optimization of waterproofing performance are crucial. This study begins with the waterproof principle of elastic sealing gaskets and deeply analyzes the factors that affect joint leakage, based on which specific optimization measures were proposed for the waterproof performance of pipe joints. Finally, to verify the actual effectiveness of these optimization measures, empirical research was conducted on a new type of shield tunnel project in Jiangxinzhou, Nanjing. The main conclusions of the study are as follows: the physical properties and durability of EPDM gaskets must strictly comply with regulatory requirements; The adhesive work of the onsite sealing gasket and the tensile deformation of the onsite pipe segment assembly on the sealing gasket is essential factors impacting the leakage of water at the joint; The solid section structure at the corner of a largediameter high water pressure shield tunnel requires to be optimized to avoid issues such as corner accumulation and stress concentration caused by the crosssectional size of the sealing gasket; The monitoring results after the tunnel is completed indicate that the optimized shield tunnel not only has good forming quality but also has a much better waterproof effect than traditional shield tunnels. This study not only provides a theoretical basis and practical guidance for the waterproof design of shield tunnel segment joints but also provides a valuable reference and inspiration for similar projects.