Abstract: Aiming at the stricter natural gas property requirements in the standard of GB 17820-2018 Natural Gas, the H₂S content in purified gas of a natural gas purification plant in Changqing Oilfield didn't meet the requirement of gas entered long-distance transportation gas pipeline. To solve the problem, HYSYS software was used to simulate the MDEA desulfurization process of the plant. The effects of solution circulation, MDEA mass fraction, tray number of absorber, feed gas temperature, feed gas pressure and lean liquid inlet temperature on H₂S and CO₂ content in purified gas were analyzed, and the parameters were sorted according to the influence degree. On this basis, a multi-parameter optimization model with minimum energy consumption as the objective function was established. The optimal operating parameter combination was obtained for satisfying H₂S mass concentration in purified gas less than 5 mg/m³ and CO₂ molar fraction in purified gas less than 2.8% by using the toolbox solution model in HYSYS. The optimization results can provide a reference for guiding the adjustment measures on the site.