As the next-generation solder, nano-copper paste has attracted wide attention in the field of power electronics due to its outstanding properties. In this paper, the effect of pressure on nano-copper sintering is investigated. It is found that the electrode of chip cannot be contacted to the nano-copper layer when no pressure is applied, whereas during the sintering there are fewer defects on the surface of nano-copper compared with that of pre-sintering under certain pressure conditions. Besides, the results of metallographic microscope confirm that the sintering quality of nano-copper has a positive relationship with pressure.