Nano Au catalyst has been studied extensively in heterogeneous catalysis due to its unique electronic and structure properties as well as high catalytic performance in various oxidation and reduction reactions. However nano Au catalysts exhibit strong sensitivity to particle size and weak activation ability towards basic substances like O2 . The formation of alloy materials with Ag and Au is one of the effective ways to solve the above problems. Various preparation methods for AuAg catalysts have been studied. The catalytic mechanism for different reactions has been explored extensively. However there is no research giving a summary to compare different preparation methods of AuAg catalysts and mechanisms of varied reactions. For this reason this study reviewed the common preparation methods and pretreatment conditions of AuAg alloy catalysts as well as their applications and catalytic reaction mechanisms in oxidation reactions such as CO oxidation and hydrogenation reactions such as unsaturated aldehyde hydrogenation. Moreover future possible directions for development were proposed. Methods By reviewing the research and application of AuAg catalysts the characteristics of different preparation methods and the influence of pretreatment conditions on the structure of AuAg catalysts as well as the catalytic mechanisms of AuAg catalysts in different reactions were analyzed. Results In terms of the preparation and pretreatment of this alloy material different preparation methods and their influence mechanisms on the loading status of this alloy particles on the carrier surface were compared. The role of pretreatment conditions in regulating the size and alloying degree of AuAg nanoparticles was also thoroughly explored. In terms of catalytic applications the addition of Ag improved the sintering resistance of nano Au. Moreover the electronic interaction between Au and Ag enhanced the activity towards typical chemicals such as O2 and significantly reduced the size-dependency of the reaction result catalyzed by a single Au material. Thus the synergy of AuAg alloy results in high catalytic efficiency towards various reaction processes such as CO oxidation alcohol oxidation unsaturated aldehyde hydrogenation alkyne hydrogenation and nitroaromatic compound reduction. Conclusion Currently there are many methods for preparing AuAg alloy nano-catalysts and the controllable and stable synthesis methods of AuAg catalysts are still the focus of future research. Meanwhile the exploration of catalytic mechanisms of AuAg catalysts in different reactions is particularly important for the directional design of AuAg catalysts and further in-depth research should be conducted to accelerate industrial applications of AuAg catalysts.