Aiming at the problem of segment floating in shield tunnel construction, based on the project of slurry shield cross-river tunnel of Nanchang Metro Line 4, through mathematical statistics method, this paper summarizes and analyzes the segment floating amount when slurry shield passes through different strata, and discusses the influence law of stratum parameters and shield tunneling parameters on segment floating. The research results show that: when driving in the full section sand layer, the floating amount of segment is small and the change of floating value is stable; when it enters the upper soft and lower hard stratum and argillaceous silt stratum, the floating amount of segment changes rapidly, especially in the weathered argillaceous silt stone of river crossing section, the floating amount of segment is the largest. Considering the single factor influence of shield tunneling parameters, with the increase of grouting pressure, slurry pressure and shield thrust, the segment buoyancy will increase, while the change of tunneling speed has little influence on segment floating during construction. In the process of tunneling, it is necessary to combine the influence of stratum characteristics on segment floating and adjust the main driving parameters in real time, which can effectively control segment floating to a certain extent.