In a fuel element product, fuel particles are randomly distributed in non-metallic materials. In order to measure the distribution uniformity of fuel particles, a heat map method based on X-ray Micro-CT three-dimensional image region statistics is proposed to characterize the uniformity. Firstly, the Micro-CT method is used to conduct three-dimensional scanning and imaging for such products, then the fuel particles are extracted through the three-dimensional image segmentation method, and then the three-dimensional image is divided into three-dimensional regions, and then the volume proportion of fuel particles in each region is counted, and finally characterized by the heat map method. The Micro-CT is used to detect and process the fuel element, and the statistical heat map is used to characterize the distribution uniformity. The distribution uniformity of fuel particles in the fuel element is visually characterized.