The desirable amine solution for the natural gas sweetening process was selected. The four parameters of yield, availability, cost, and operational conditions were selected as criteria of this process. Also, seven alternatives (amine solution) were proposed for ascertaining the best amine solution. According to the objectives functions (The reduction of acid gas contents and reboiler duty), the simulation results reveal the best of feed gas temperature, and MEA concentration is 45ºC and 40 wt.%, respectively. In this condition, the MEA solution consumption decreased by 2% and reboiler duty reduced 0.01% , respectively.