Abstarct: Benches are one of most important parameters in geometry of open pit mines. Various factors affect to selecting the dimensions of the benches and finally the final shape of the open pit mines. The role of bench height is more highlight and important than other dimensions of the benches, Because the dimensions of other bench components (such as bench width and face angle) directly depend on the bench height and follow it. Many factors such as overall pit slope angle, the size of extraction equipment, dilution and ore lose, and the mining selectivity, are dependent on the bench height. The mines, depending on their goals, use different bench height. In this research, a new approach is proposed in order to select the most suitable economical bench height. For this purpose, exploration data of iron ore mine #2 Gol-e-Gohar has been used and Four scenarios of bench height (6, 9, 12 and 15 m) have been investigated. Effect of various scenarios on the bench height in the amount of ore tonnage, average grade, mextal content, blasting pattern and select of drilling, loading and hauling equipment were checked. Firstly, GEOVIA GEMS software was developed for geological model of the deposit. Also, for each scenario, pit design were done and the amount of waste and ore tonnage in each scenario were estimated. Then, the amount of operating and capital costs for each scenario were estimated. Regarding these costs, the discounted cash flow table were calculated and net persent value (NPV) for scenarios were compared. The results showed that the highest amount of ore recovery was obtained for the bench with 15-meter height, but the maximum net present value is related to the 12-meter bench height for a hydraulic shovel.