The aim of this paper is to establish a digital model for characterizing the actual pore structure of coal and further simulating the gas seepage in coal. The computed tomography (CT) data of long-flame coal samples from Daliuta coalmine is obtained through the μCT225kVFCB high precision CT system. It is found that the minimum pore diameter in coal sample is 1.94 μm. Meanwhile, a new method is developed to convert CT three-dimensional (3D) data into CAD digital model, according to the reverse engineering technology and a Matlab language based 3D reconstruction program. As an example, a finite element model is established by Ansys software to simulate the gas seepage. Then the distributions of gas velocity and pressure in the coal pores are analyzed and hydraulic conductivities along X, Y and Z directions are also calculated. The results indicate that the permeability of coal exhibits anisotropy at microscale (<100 μm) and is greatly affected by coal structure. The newly developed CAD digital coal model can be used not only for finite element analysis, but also for discrete element analysis such as EDEM software. Therefore, this study broadens the application of 3D CT data and extends research areas of coal at microscale.