The different microstructures of Silver-Copper/Molybdenum Disulfide (Ag-Cu/MoS 2 ) composites were manufactured by hot press and hot extrusion processes to investigate the electrical tribological behaviors of both the hot-pressed and hot-extruded composites under air and vacuum. The results showed that microstructures and properties of Ag-Cu/MoS 2 composites were improved by hot extrusion, which decreased the wear rates rapidly in both air and vacuum.In air, the hot extrusion could improve transferred layer and tribo-film, resulting in a significant decrease in contact voltage drop, which goes from more than 70 mV in the hot-pressed composite, to 30 mV at the hot-extruded composite. Under vacuum condition, some wear debris was melted on the worn surface and then transferred to counterface to form the transferred layers which lead to the lower contact voltage drops under vacuum, about 6 mV in hot-pressed Tribology Transactions ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 composite and 3 mV in hot-extruded composites. In addition, the severe adhesive and abrasive were attributed to the molten wear debris and transferred layer, resulting in the dramatic fluctuation of friction coefficient in vacuum.