In design, construction and maintenance of any engineering system, engineers have to take many technological and managerial decisions at several stages. The ultimate goal of all such decisions is either to minimize the effort required or to maximize the desire benefit. Optimization can be defined as the process of finding the condition that give maximum or minimum value of function. Thus, study was conducted for exploring about concept of ‘Optimization of structure’ i.e. ‘Optimization of swimming pool’. The swimming pool means any structure, basin, chamber or tank containing an artificial body of water for swimming, diving, recreational bathing. Considering the underground rectangular swimming pool, the vertical wall of such structure is subjected to hydro-static pressure and soil pressure & the base is subjected to weight of water and uplift soil pressure and it is designed by using Indian Standards. This paper focused on the optimum cost design of swimming pool due to effects of variation in grade of concrete and for different capacity by change in height (Depth). The main aim is to achieve the economy. Material saving results in saving in construction cost at the same time the safety is also considered. The model is analyzed and design by using MATLAB software. Optimization is formulated is in nonlinear programming problem (NLPP) by using sequential unconstrained minimization technique (SUMT).