Abstract: This study investigates the complex heat transfer characteristics and influencing factors of the sodium pool in the pool-type sodium-cooled fast reactor（SFR）, which is filled with high-temperature liquid sodium and covered with argon gas. Heat is mainly transferred to the reactor vessel superstructure and argon space by radiation and convection. The presence of radiation emissivity and the aerosol layer, resulting from the evaporation of liquid sodium, affects the thermal and hydraulic characteristics of the main vessel superstructure. Therefore, to ensure the safety of the reactor vessel superstructure under different temperature loads, it is crucial to determine the temperature distribution under different radiation emissivity and aerosol layer conditions. In this study, numerical simulations of the roof slab of the reactor vessel upper part in the pool-type SFR were conducted to determine the temperature field of the roof slab under the influence of different emissivity and aerosol layer thickness. The results show that increasing the emissivity of the radiation heat exchange by 53% increases the temperature of the roof slab sloping shoulder and argon space by 31.47%, while decreasing the Grashof number（Gr） by 19.29%, thereby enhancing the radiative heat exchange effect and weakening the natural convection effect. Furthermore, increasing the aerosol layer thickness in the height near the sodium surface（0～0.2 m） increases the local temperature of the argon space. However, the effect on the temperature of the roof slab sloping shoulder is limited. Increasing the height of the aerosol layer from 0 to 0～0.1 m decreases the radiation heat through the aerosol layer exchange by 22.68%, while decreasing the Gr by 19.29%. However, increasing the height of the aerosol layer from 0～0.1 m to 0～0.2 m only slightly decreases the radiative heat through the aerosol layer exchange by 0.04% and increases the Gr by 0.09%, weakening the radiative heat exchange and enhancing the natural convection effects.