Plate of Ni-clad 316H stainless steel was prepared via hot rolling process after pre-heating at 1200^oC for 120 minutes, then concurrently the rolling process was interrupted after rolling for 3, 5, and 7 passes respectively, while the relevant samples are taken and water-quenched for subsequent characterization in terms of the evolution of their interface-composition and -morphology, as well as the formed oxides there. Results show that until the 3rd rolling pass, the rolling plate temperature was about 1000°C, the two metals were closely bounded with equiaxed grains of slightly distorted microstructure on both sides of the interface and the inter-diffusion of elements for the two metals was not obvious; Until the 5th rolling pass, the plate temperature was about 940°C, the grains of 316H were elongated with significant lattice distortion, whereas, obvious inter-diffusion can be found near the interface; Until the 7th rolling pass, the plate temperature was about 880°C, large number of elongated and distorted grains were observed on the 316H steel side and a fine grain structure crushed by hot rolling distributed near the interface. The elements of Ni, Fe and Cr were fully inter-diffused near the interface, but the less motionable Mo enriched at the 316H side. The grains of Ni layer coarsened obviously. The interface evolution of Ni/stainless steel composite plate during the rolling process follows the so called three-stage theory and N. Bay's theory. The physical contact stage and the physical-chemical contact stage happened between the 3rd and 5th pass. Then the rolling from 5th to 7th pass was the final physical-chemical contact phase, whilst the inter-diffusion begins, that is, the "bulk" mutual phase begins. In the high-temperature and low-oxygen environment, the Mn oxides near the interface might form during the rolling process. The oxide was crushed and squeezed toward the substrate by the rolling force, therefore distributed in chains near the interface eventually.