Abstract：The characters of microstructure and crack change in concrete can be investigated by CT images.But now there is rare quantitative analysis of concrete CT images in China. Damage-fracture evolution theory has been applied to the quantitative analysis of concrete CT images. In such a way，the degrees of perfection and damage are used to analyze the strength of each variation，which solves the question that the distribution range of CT numbers is too wide. The transition from microscopic analysis to macroscopic one is accomplished on the basis of l-level perfect field and l-level damage-fracture field. Furthermore，the areas of cracks，aggregates，mortar and air are extracted from CT images according to l1–l2 level intercepted section. Then，the approach to measure the size of each area has been put forward，which has realized the description of each substantial distribution. Based on this method，the application prospect of damage-fracture evolution theory to the experimental study on concrete CT image is discussed.
