The effects of plate surface mechanical rolling treatment (P-SMRT) on the microstructure and tribological behavior of Inconel 625 alloy were investigated. The results reveal that P-SMRT induced the formation of a gradient nanostructure (GNS) strengthening layer with a thickness of 700 μm on the surface of Inconel 625 alloy. The GNS formation was driven by the interaction between deformation twins and dislocations, leading to the development of shear bands that transformed into ultrafine grains and nanograins. The hardness of the samples with GNS was 192.7% higher than that of the untreated samples. In addition, the tribological properties of the P-SMRT and untreated samples were investigated through dry sliding friction and wear tests. These findings indicate that the P-SMRT induced GNS accommodated greater strain, reduced strain localization, and inhibited surface material exfoliation and transfer, thereby significantly enhancing the wear resistance of Inconel 625 alloy.