In order to strengthen the research on the distribution relationship between ore microcracks and target minerals，and improve the role of mineralogy of hydrometallurgy process，ores from  Mianhuakeng uranium deposit was studied as the case of three-dimensional X-ray microscopic CT technology.  The 3D X-ray microscopic CT was used to processing and comparing the parameters of metallic minerals and pores in raw ore. The results showed that the mineral composition of the uranium ore is simple，and the harmful components affecting the metallurgy are few. Uranium exists in the form of pitchblende，uranium-black and uranophane，which are easy to be leached. Some of the pitchblendes fill mineral cracks or dissolution pores. The distribution form and regional overlap between microcracks and metallic minerals such as uranium minerals are low，which may lead to insufficient contact between the leaching solution and uranium minerals，thus affecting the leaching effect. Further fine grinding of ores from Mianhuakeng uranium deposit can improve the degree of liberation of ultrafine uranium minerals and improve the heap leaching effect. By introducing CT technology，the three-dimensional morphology and distribution images of different components in ore particles are extracted effectively，and the volume proportion of different components was calculated. The parameters obtained by this method are relatively reliable and stable，which has reference value.