This paper describes a methodology to develop the interface between a finite element software and optimization algorithm for optimization of concrete high ARCH DAMS. The objective function is the volume of the dam. The numbers of design variables are 31 including the thickness and upstream profile of crown cantilever, left and right abutment thickness, radius of curvature of water and air face left and right by use of polynomial curve fitting and cubic spline function. The constraint conditions are the geometric shape, stress and the stability against sliding. Initially, a program is developed in MATLAB in order to generate the coordinate of nodes, then finite element software ANSYS is taken for modeling the geometry of dam. Finally, the optimization technique is performed by Simultaneous Perturbation Stochastic Approximation algorithm. To include dead weight of dam body, stage construction is considered. The proposed method is applied successfully to an ARCH dam and good results are achieved. The results indicate that the concrete volume of the dam optimized is reduced by an average 21%. Compared with the initial shape, the time of convergence of this method is very short and the method is fairly effective. It can be applied to practical engineering design.