Since the discontinuous deformation analysis method (DDA) has been developed， more and more advantages are being displayed in simulating large displacement and deformation of the system of discrete bodies. In this method， however， some artificial parameters have to be preset， which more or less affect the results. By means of a simple model involving only one slide body， the effects of those artificial parameters such as the step length and the stiffness of contact springs on the results are analyzed. It is pointed out that only in the proper ranges the larger time steps and larger stiffness can give rise to better computational results. Some reasons of leading to theses results ate discussed. The lower bounds and the upper bounds for the artificial parameters are suggested.