The sluice gates are widely used for flow regulating and discharge measuring in irrigation and drainage projects. For this reason, determination of the discharge coefficient for sluice gates is an important issue. Sluice gate discharge coefficient depends on geometric and hydraulic parameters of the flow and type of gate. In this study, with a simultaneous solution of Bernoulli and momentum equations and regression techniques, effective non-dimensional parameters in determining the discharge coefficient and the relation of these parameters and discharge coefficient were determined. Also comparison between some analytic and experimental results for determining discharge coefficient was carried out. Results showed that the nonlinear equation got better results in comparison with the linear equation in modeling discharge coefficient. All numerical computations in procedure of this study were performed by Wolfram Mathematica v.6 software.