To explore the influence of fluorine (F) on mantle minerals and its behaviors during subducting, we investigated the compressibility of F-bearing superhydrous phase B (Shy-B) using synchrotron-based single-crystal X-ray diffraction combined with diamond anvil cells up to 27 GPa and 750 K. Our results show that the presence of F can largely enhance the incompressibility of Shy-B. Based on the obtained thermal elastic parameters, density and velocity profiles are evaluated along cold and warm slabs. Our results demonstrate that addition of F enhances the density (~1.3-1.7%) and the bulk velocity (~1.0-2.4%) of Shy-B relative to OH end-member at uppermost lower mantle conditions. The decomposition of F-bearing Shy-B would lead to an abrupt increase in density (~8.9-10.5%) and a small increase in bulk velocity (~0.7-1.8%). The combined results could provide constraints for modeling the geodynamic process related to subduction and transportation of F and OH into lower mantle.