Abstract: Mg₂Si-based thermoelectric material is one of the promising thermoelectric materials in the middle-temperature range.To improve the interfacial properties of Mg₂Si based thermoelectric joints, a novel electrode material Mg₂SiNi₃ used as Mg₂Si electrode material was proposed, and the connection between Mg₂SiNi₃ and Mg₂Si was realized by discharge plasma sintering (SPS). At the same time, the interfacial morphology, interfacial electrical properties, mechanical properties and stability of the joints were analyzed.The results show that the Mg₂SiNi₃ and the Mg₂Si have formed a complete metallurgical bond after sintering, and all the components at the interface have achieved uniform transition.The interface contact resistance is optimized effectively, and the joints have good interfacial stability. Before and after aging, no significant degradation of interface performance occurs. The proposed Mg₂SiNi₃ provides a new idea for the design and integration of Mg₂Si-based thermal appliances.