This research paper presents design point simulation of three shaft industrial gas turbine i.e. SGT500 using a combination of random and gradient optimization algorithm. The modeling of design point of gas turbine is crucial initial step as it will help in simulating the complex step of off-design model. Hence, accuracy of the gas turbine model at design point will influence the rest of the model and its forthcoming results. The proposed algorithm suggest problem formulation of the multi-objective figure of merit that yields most accurate results. By using GasTurb14 software the SGT500 engine will be adopted to know all of its unknown design variables along all the stations. The design point is selected at the optimum operating point of the gas turbine which is 19.1 MW. The targeted performance variables taken are heat rate, thermal efficiency, power output, exhaust gas temperature, exhaust mass flow, and pressure ratio. The results are validated and show average accuracy of more than 99.9. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.