The common natural gas purification facilites are mainly consisting of desulfurization, dehydration, sulfur recovery, tail gas treatment, acid water extraction and other units, among which the desulfurization unit is the most important process unit and energy consumer of the whole gas purification facilities. During the operation of desulfurization unit, the real time fluctuation of feed material has an important impact on the stable operation of natural gas purification plant. Based on the desulfurization unit of a natural gas purification plant, the steady-state simulation model and dynamic model were successively built using HYSYS software, and validated using the actual operation data. By adding disturbance to the parameters of natural gas feed material (flow rate, temperature), the transient state of the desulfurization unit is simulated, and by adjusting control parameters, the energy consumption fluctuation time is shortened, so that the equipment can recover quickly back to steady state operation, and the impact of fluctuations in feed parameters on the equipment operation is reduced. The analysis of the change of total energy consumption of natural gas desulfurization unit in the transient state shows that when the feed parameters fluctuate, the total energy consumption of the unit will fluctuate, especially when the flow rate and temperature decrease, the energy consumption fluctuation is more obvious.