Abstract: The stable FeO nanofluid was prepared in this work. The ammonia bubble absorption experiments for FeO nanofluid-based solution and water-based solution were carried out and compared under the two different conditions of constant flow flux and constant inlet pressure of ammonia gas，respectively. The results showed that the absorption effect of ammonia was enhanced by the prepared FeO nanofluid. At a constant flow rate of ammonia gas，the enhanced absorption effect was not observed until several minutes later from the beginning of the absorption process. Under the condition of constant inlet pressure，the absorption effect was observed immediately at the very beginning of the absorption process. The possible reasons for the above enhancement phenomenon were also given.