Based on surface chemistry, the force status of capillary pores of concrete is analyzed and the mechanical model of a single capillary pore in concrete is built with use of ANSYS, a sort of software for analysis and calculation. Then drying shrinkage strain of concrete is simulated. With the continuous evaporation of water, when the radius of concave water surface drop to a certain value, the corresponding shrinkage strain of concrete can be approximately calculated out. Finally the curve of gradually increasing concrete volume-shrinkage strain versus the decreasing radius of concave water surface is described. The existed errors of this simulation are analyzed,and some suggestion for improvements is given.