Abstract: In this paper the elastic-plastic finite element calculation for the deformation at the tip of a propagating crack was conducted using a model based on large deformation, and simulation by combining both method of shifting and relaxing of the crack-tip nodes. The calculated results indicate that, during the process of stable crack growth, both the crack opening displacement, between the upper and lower crack surfaces at a fixed distance r_m behind the current crack tip δ_m, and the crack tip opening angle (CTOA)_m remain constant, which were found to be in good agreement with experimental observations. This implicates that the crack opening displacement δ and the crack tip opening angle CTOA are the essential factors controlling the ductile crack growth.