In order to quantify the degree of restraint in the restrained elliptical ring， a numerical analysis method was adopted to simulate concrete shrinkage under restrained condition through applying fictitious temperature field on concrete. The free shrinkage and restraint shrinkage displacements at concrete inner boundary along the major axial of elliptical were derived to calculate the degree of restraint. The effects of concrete ring thickness， steel ring thickness and concrete elastic modulus on degree of restraint were discussed. In addition， the formula of degree of restraint for elliptical ring specimen was fitted based on the numerical results. The concrete cracking time based on the numerical analysis was in reasonable agreement with the experimental result， which verified the numerical method. Finally， a design approach of restrained ring test was recommended to assess crack resistance of concrete structural under various degrees of restraint.