Abstract: As the water pressure of shield tunnel increases, the key to tunnel construction is to strengthen the water resistance of joints. By analyzing the characteristics of stress and deformation of the gaskets in the joints of tunnel segments, a mechanical model is established, and a formula for the surface contact pressure of the gaskets under lateral water pressure is deduced theoretically. According to the constitution of surface contact pressure, the bearing seal resistance and self seal resistance are quantified. It is concluded that the contact area, elastic modulus and thickness of the gaskets, effective sectional area, elastic modulus, effective tightening length of bolts and other factors have influences on the water resistance. Based on an engineering example, the water pressure resistance tests and assembly tests are carried out on the gaskets of shield tunnel segments. Through the interpretation of experimental phenomena and the data analysis, it may provide a reference for the following design and production of the gaskets in the joints of tunnel segments as well as the construction of shield tunnel.