Abstarct: Design of open pit slope angles is becoming more and more important as the mining depths of open pits continuously increase. Small changes in the overall pit slope angle have large consequences on the overall economy of the mining operation. The case in particular in this study is the Shams Abad Iron Ore open pit mine in central Iran. A major complication of increasing mine depth, is the increased risk of sustainability. Failure in the final slope of pit, could be potential. Retaining pit slope angles is very important to reduce stripping that could have a direct impact on the economics of mining. Design of pit ultimate limit in addition to important parameters such as production cost, is dependent on rock mass strength and stability. For this reason, the potential of failure for first design and design of the final pit should be evaluated. Level bench, internal ramp and overall slope angle should be considered to measure the stability of each bench. Single benches, internal ramp areas of pit for a while can be stable, while they may have a potential instability in the final slope of pit. In this research work, the slope stability of Shams Abad iron ore mine is investigated by experimental method, limit equilibrium method and numerical modeling (with FLAC software), in addition to the technical and practical studies of slope stability and the investigation of possible failure, suggestions for future research in this mine are presented. The results of the failure analysis indicate that, in the Shams Abad mine less occures controlled failures like plane failure and wedge failure. In this mine occures toppling failures. Results obtained from design methods show that the amount of RMR suitable is obtained for Shams Abad rock mass in the experimental method, the slope and the height of mine are stable in the scale of the stairs and the final slope. In the limit equilibrium method is obtained an appropriate safety coefficient for the mine. In numerical method, the safety factor shows this mine is stable on the benches scale and final wall. In this mine the displacements are acceptable and indicate sustainability in two scale.