Abstract: In recent years, the design and preparation of bimetallic non-homogeneous synergistic catalysts have become a hot research topic in the field of materials and catalysis. The appropriate combination of two components often greatly improves the catalytic performance of the catalysts, and the degree of this catalytic performance improvement is significantly greater than that of the catalytic performance when used alone, thus it is believed that there exists a synergistic catalytic effect between the components. In the past decade, bimetallic synergistic catalysts have made great progress in the fields of low-temperature fuel cells and water splitting. This paper summarizes the relevant researches of bimetallic synergistic catalysts in the field of electrochemistry in recent years, and systematically reviews the synergistic reaction mechanism and research progress of three typical bimetallic synergistic catalysts, namely PtRu, NiFe and PtNi, in the areas of methanol oxidation reactions, oxygen evolution reaction, and oxygen reduction reactions, the details are as follows: (1) PtRu bimetallic supported materials are considered the holy grail of electrocatalysts that are widely used in fuel cell-related electrocatalysis of methanol oxidation reaction. The unique catalytic ability comes from the synergy effect of PtRu, which cannot be realized by other Pt alloys. The promotion mechanism of PtRu-based catalysts in electrocatalytic reactions is reviewed in recent years for investigation of the role of Pt and Ru during the catalytic reaction process, respectively. To be specific, Pt promotes dissociative dehydrogenation of methanol molecules, while the addition of oxophilic metal Ru can increase the electron density around Pt and weaken the strength of the bond between Pt and adsorbed CO. Furthermore, Ru facilitates the dissociation of H₂O at a lower potential to form adsorbed hydroxyl groups which act as oxidants to promote the oxidation of CO adsorbed on the nearby Pt. (2) Since the synergistic effect of Ni and Fe is beneficial to reduce the reaction energy barrier of oxygen evolution reaction, NiFe based catalyst represents a very promising non-precious metal OER catalyst. This review focuses on the optimization strategies for NiFe based catalysts, summarizes the research progress made in recent years, and discusses the mechanisms involved in these strategies. In particular, it is discussed whether the active site center of the catalyst is the Fe center, the Ni center or Fe Ni dual center. (3) Since the most significant progress has been made on Pt₃Ni alloy, nanoscale PtNi alloy octahedra enclosed by (111) facets have emerged as promising electrocatalysts toward the ORR. We review the important recent developments of PtNi octahedral electrocatalysts including synthetic strategies, relationship between structure and performance, mechanisms during ORR process. Specifically, the present review focuses on the synergistic effect of Ni and Pt to improve the ORR performance, and the active site center of PtNi alloy electrocatalyst. In summary, the field of bimetallic nano-catalytic materials has achieved significant development such as PtRu, NiFe and PtNi. Nevertheless, there are still many challenges in the performance of these catalysts due to a variety of factors, which need to be fully considered in the bimetallic catalyst materials. In addition, novel characterization methods can also be used for the bimetallic nanocatalyst materials and the study of the synergistic catalytic mechanisms. For example, the wide application of spherical aberration corrected transmission electron microscope (ACTEM) can be used to obtain complete surface information through detailed observation of the nanocatalysts. Through the analysis of X-ray absorption fine structure spectroscopy (XAFS), the oxidation state of the absorbing elements, the distance of the absorbing atoms to the neighbouring atoms, and the number and type of atoms, etc. can be used to deeply understand the catalytic reaction steps of bimetallic nano-catalysts. Meanwhile, the application of computational simulation has also been increasingly important in the investigation of catalytic reaction mechanisms. Therefore, the combination of computational simulation and experiment results can not only increase the comprehensive understanding of the catalytic reaction process, but also help to provide a reliable theoretical basis for the design of highly efficient bimetallic catalyst materials in the future.