The work aims to study tribological properties of self-mated copper under synergistic lubrication of ionic liquid-silver film (electroless silver film and electroplated silver film) under a high contact stress, and compare the electroless silver film and electroplated sliver film. The electroless sliver film and electroplating silver film was prepared separately on T2 copper substrate. Tribological properties of two silver films (disk) and copper (pin) lubricated by ionic liquid LP108 were evaluated with a disk- pin contact reciprocating friction and wear tribo-meter at average Hertz contact stress of 0.77 GPa and sliding speed of 0.76 mm/s. The unlubricated self-mated copper had high friction coefficient of 2.5 and suffered severe adhesive wear. Moderate adhesive wear occurred on the self-mated copper lubricated by ionic liquid LP108. The synergistic lubrication of ionic liquid and silver film could effectively improve tribological properties of self-mated copper. Steady-state friction coefficient of the electroplated silver film was nearly 0.5, and that of electroless silver film was nearly 0.3. The electroless silver film exhibited better anti-sticking property. The synergistic lubrication of ionic liquid-silver film effectively reduces adhesion of self-mated copper under high contact stress, and further improves its tribological properties. The electroless silver film has excellent anti-sticking property under ionic liquid lubrication due to the formation of thin transfer film (pin) and friction layer (disk) on friction interface.