Development of the Sino-Russian relations during the past 20 years – from friendly to constructive relations and up to the relations of strategic partnership – is elaborately dwelt upon in this article by two ladies researchers from the Peking university. Among the many important problems dealt with, special attention is paid to the settlement that the two countries’ inveterate boundary problems finally received after the demarcation of 4300 km of the Sino-Russian boundary at the end of the 40 years of national boundary negotiations.