Abstract: The source and influence of iron ion in alkanolamine desulfurization solution were studied by analyzing the sample and carrying out the simulation experiment. The results showed that the increase of iron ion content in alkanolamine desulfurization solution was due to the formation of corrosion products, such as ferrous carbonate and ferrous acetate, which had high solubility; while the iron ion content in the desulfurization solution increased, the iron ion will react with the hydrogen sulfide to generate ferrous sulfide precipitation, and the ferrous sulfide precipitation will accumulate continuously and block the tray and rich liquid filter, ultimately lead to unit liquid flooding.