The model of capillary pores in concrete was established and the strain of drying shrinkage of concrete was simulated and calculated by ANSYS, that is a variety of computer software for finite element analysis on the basis of the theory of capillary tension of concrete. It assume that the surface tension of water in concrete was a constant and the radius of principal curvature drop into different values in turn, the radial shrinkage displacement of capillary pores, the volume shrinkage strain of a single pore and the whole concrete were calculated. The corresponding volume shrinkage strain were work out of a single pore and the whole concrete by using the same method, when assuming that the extent to which the radius of principal curvature of the curved meniscus descend was same and that the surface tension take less and less value in turn, the curves were plot at of the volume shrinkage strain of concrete along with the change of the radius of principal curvature of the curved meniscus and the surface tension of capillary water respectively. So the relationship among the drying shrinkage of concrete, the surface tension of water solution and the principal curvature of the curved meniscus in capillary pores of concrete was found out approximately.From the microscopic point, the estimation model of concrete drying-shrinkage strain was established.