In order to further clarify the influence of buoyancy on the regeneration cooling effect of aviation kerosene, and to provide theoretical support for improving the regeneration cooling effect, this paper established an RNG k-ε turbulence three-dimensional model, which was verified by comparing the wall temperature obtained by other experiments and simulations under the same conditions. Aiming at the variation of temperature distribution, secondary flow velocity, convective heat transfer coefficient and turbulent kinetic energy induced by the buoyancy of the aviation kerosene RP-3 in the horizontal pipe under different gravity conditions, the effect of jet fuel buoyancy on the heat transfer flow is discussed. The research results show that the increase of gravity will significantly increase the influence of buoyancy on convection, and the turbulent kinetic energy will increase nonlinearly, and the convective heat transfer coefficient will be significantly improved. When the gravitational conditions change, the secondary flow induced by buoyancy in the direction of gravity undergoes a complicated evolution. The convective heat transfer coefficient first decreases, then increases, and finally decreases. When the temperature of aviation kerosene exceeds the supercritical temperature, the convective heat transfer coefficient changes abruptly, causing significant differences in the wall temperature.