The decommissioning treatment project of a uranium mine needs to excavate and treat the tailings of the tailings and polluted soil in the tailings pond. How to quickly determine the radionuclide activity concentration in the contaminated soil and determine the excavation depth in different areas has become the key of the project. The migration behavior of uranium and radium was studied through field investigation, sampling analysis and model verification. The results show that, the depth of soil pollution around the tailings pond is 70.9 cm, the distribution of radium activity concentration in the tailings heap soil with depth conforms to the Bigaussian distribution, the deepest depth of pollution removal is predicted to be 22.0 m, the uranium radium ratio in the soil at the bottom of the tailings pond is linear with the soil depth, and the 3D model of the tailings pond of the mine is established by using surfer drawing software. This study can provide theoretical and technical support for the relocation and treatment of the tailings pond of the uranium mine.