In order to obtain the surface crack development, displacement information of uranium tailing dam conveniently, and evaluate the interrelationship between surface damage and radon migration changes, this paper constructed an indoor model based and built a binocular camera using smartphones to obtain the model surface image data under the multi-stage simulated seismic loading. Image processing techniques were used to quantify surface cracks and displacements, and radon meters recorded radon release data. The results showed that the surface crack of the model was positively correlated with the loading strength. At 0.9 g, the crack rate reached 3.27%, and the free surface caused by the crack led to multiple traction failures; The maximum displacement of artificial markers on the slope increased steadily from 7.748 mm after 0.3 g to 19.45 mm after 0.7 g, and then surged to 46.52 mm after 0.9 g; The stronger the simulated earthquake intensity, the higher the concentration of radon released by the model. The trend of radon release was consistent with the crack and displacement, but the rate of change was more synchronized with the displacement. The technique is expected to provide an economical and intuitive method for dam engineering and environmental safety evaluation.