Abstract: Base on the Reynolds time averaged N-S equation and Renormalization group (RNG) k-ε two equation turbulence model, this paper studies and analyzes the hydraulic performance and the pressure fluctuation distribution characteristics of the axial-flow LBE pump in room temperature, clear water and liquid LBE. The results show that: for the hydraulic design of the axial-flow pump completed according to hydraulic design method of clear water medium and relevant empirical coefficient, under the condition of LBE medium, the head and the efficiency of the pump are improved, the head increases obviously with the increasing of the flow, and the phenomenon of flow separation in the inner boundary layer of the pump is obviously weakened under the LBE medium. The main frequency of the pressure coefficient fluctuation at the inlet monitoring point of the pump impeller is 81hz, which is equal to the blade rotation frequency, and the second frequency harmonic occurs at two and three times of the blade frequency; the medium viscosity does not affect the pressure fluctuation coefficient amplitude at the inlet of the impeller, and the medium density, that is, the inertial force, is linearly positively related to the pressure fluctuation amplitude at the inlet of the pump impeller.