Abstract: Currently, the energy consumption of natural gas purification unit is high. In this paper, a process model for sour gas purification unit has been completed using HYSYS based on the purification process and operating parameters of a unit with 50×10⁴ m³/d purifying capacity. The effect of main process parameters in the H₂S content of feed gas, quality fraction of MDEA in hydramine, H₂S's loading in lean gas and flowrate of stripping gas on the energy consumption of purification unit have been studied based on the model. The results show that if the H₂S content of feed gas rises, the energy consumption of desulfurizing device will go up, dewatering device independent. With the increase of MDEA's quality fraction of hydramine absorbent rises, the energy consumption of the desulfurizing device will go down, and increasing the flowrate of stripping gas can decrease the energy consumption of the dewatering device. Contribution to the different factors to the purification unit, adjusting the running parameters can reduce the energy consumption by 12.8%.