Abstract: Experimental research on the heat transfer characteristics of boiling two-phase sodium flowing in an annuli was done. Experimental conditions were system pressure from 3.6 to 110.0 kPa, heat flux from 11 to 600 kW•m^-2 and velocity from 0.02 to 0.45 m•s^-1. The experimental results show that the boiling heat transfer coefficient of sodium is affected significantly by the heat flux and system pressure instead of the inlet subcooling or mass flow rate. On the base of the experimental data, a correlation of the heat transfer coefficient for boiling sodium was proposed. Applicability of this correlation to the liquid metal sodium boiling in an annuli was proved by comparing the correlation results to those experimental data.