Abstract: During erection of shield tunnel segments, gasket experiences the time-variant scenario of "compression before joint staggering". The ANSYS is used to build the three-dimensional finite element model of gasket and groove, and the loading mode of "compression before joint staggering" that more closely resembles the construction process characteristics is used to conduct numerical simulation study on water resistance and to conduct comparative analysis of the conditions without consideration of the compression-joint staggering time-variant sequence. As the results suggest, the water resistance of the gasket with "compression before joint staggering" is superior to that of the gasket with "joint staggering before compression"; compression will create great friction between the gasket contact surfaces, so upon joint staggering of the gasket, the gasket contact surfaces will not be completely staggered, and the overall deformation pattern is in one-sided inclination; with hydraulic pressure considered, the water resistance of the gasket with "compression before joint staggering" is better than that in the condition without hydraulic pressure, which indicates that hydraulic pressure further compresses the gasket and thus increases the surface contact stress and enhances the water resistance.