Abstarct: Concrete is a material that is widely used in structures. The Engineering and performance properties of concrete depends on both The structural features And the properties of its components that usually assessment in the laboratory. Design and analysis of concrete structures mainly baxsed on the assumption that the concrete can be considered as a homogeneous material, While it is a heterogeneous composite consisting of aggregate, cement paste and air Voids and Interfacial transition zone (ITZ). In this study the 2D and 3D meso scale finite element model of concrete specimen in Abaqus using CT scan image processing is developed To be able by defining mechanical properties of concrete constituent materials, to determine microstructure of models and mechanical properties numerically. Thus we can reduce large volumes of laboratory operations and determine properties of concrete numerically. A Matlab code for processing three dimensional tomographic X-ray images (X-ray) concrete samples written. The Images has been prepared by using a CT scanner at the shahid Rajaee Tehran Heart Center. A general frxamework of quantitative computational tomography (QCT) to build a three dimensional Image of the concrete samples is used. The aim of this study is develop a new method to determine the actual concrete compressive strength numerically. In this study, finite element models for two types of cubic and cylindrical concrete samples using CT scan images and also concrete damage plasticity(CDP) combination model was created in Abaqus. And also by using this model the Failure and crack patterns of concrete in compression and tension can be evaluate