The monitoring data of a rivercrossing shield tunnel in Shanghai and the tidal fluctuation above the tunnel are analyzed by data statistical analysis method, correlation analysis method and periodicity analysis method, so as to learn the relationship between tidal fluctuation and deformation and convergence of rivercrossing shield tunnel. The results show that: 1) The even settlement would occur at tunnel section in river; and the settlement fluctuation and tidal fluctuation show similar periodicity. 2) The settlement fluctuation of tunnel section on land is related to the distance between tunnel and the river. 3) The tidal fluctuation induced cyclic convergent deformation of transverse diameter crosssection of tunnel segment is larger than that of vertical diameter of crosssection of tunnel segment. The study results can provide reference for design, construction and maintenance of rivercrossing shield tunnel.