Abstract: Uranium tailings and surface heap leaching of uranium ore are particle-packing emanation media, and the effect of the inner water level and the thickness of the overlying water on the migration and emanation of radon can not be ignored. In order to reveal the law of radon emanation on the surface of the media, according to the Fick’s law and the radon transfer theory in air-water interface, one-dimensional diffusion-transfer mathematical model of radon in the water-immersing particle-packing emanation media was established, and the analytical solution of radon concentration in the air-water two-phase system under the steady state conditions and the radon exhalation rate calculation formula were obtained. When the water level is 0 m, the surface radon exhalation rate of particle-packing emanation media increases with the thickness of particle-packing emanation media, and the growth rate decreases with the increase of the thickness. The surface radon exhalation rate first increases with the water thickness and then decreases. When the height of water is greater than the thickness of emanation media, the surface radon exhalation rate decreases with the increase of the thickness of the overlying water, and increases with the increase of the radon diffusion coefficient.