It is great important for the development of China’s uranium mining to efficiently extract low seepage sandstone uranium ore rock. It is the objective of this paper to present the effects of the structural characteristics of the low seepage sandstone uranium ore rock on permeability. Samples of sandstone from a uranium mine in XinJiang province were used to carry out experimental research on permeability. These tests were carried out on ore rock with particle size and distribution characteristics determined by a homemade permeability test device. The research indicates that the sandstone uranium deposits may be classified as low seepage because the particle size falls within the range 0.1~1.6mm, that the distribution of particle sizes observed conforms to low seepage fractal characteristics, the permeability decreases when the value of the ore particle size distribution of fractal dimensions increases, and the permeability decreases with particle size decreasing, and that the decrease of the permeability is not a linear change, but is an obviously exponentially decreasing functional relationship.