How did revolutions facilitate empires’ transition to nation-states? This article compares the Bolshevik and the Chinese Communist Revolutions. It conceptualizes this Soviet–Sino comparison through three dimensions of nation-building: separating from a universal community, building a national cultural core and overcoming internal ethnopolitics. Both socialist regimes accommodated the nation-state model by fusing centralized control with limited autonomy for ethnic minorities. Yet, whereas the Soviet Union claimed to be a universal union of nation-states, which was supposed to keep accepting new members until it covered the entire globe, the People’s Republic of China resembled a typical nation-state that preserved multiethnicity and enclosed borders under the title of the ‘Chinese Nation’. In analyzing the influence of revolutions, this article probes three relations: inter-revolution, revolution–society and revolution–counterrevolution. Arising after the Bolsheviks as a follower-revolution, the Chinese Communist Party (CCP) was confined to a national component of the USSR’s global communism project. This shaped the CCP’s enclosed geographical activity space, Han-dominated ethnic composition and the consciousness of national liberation. The CCP’s mobilization covered far wider social strata than the Bolsheviks’ had, which engendered stronger manpower and motivation to transform the traditional culture into a national culture. Being weak at its borderlands, the CCP was cautious about the doctrine of ‘national self-determination’, not daring to make it a geopolitical weapon for revolution export as the Bolsheviks had done in founding the Soviet Union. Owing to each of these differences in revolutionary trajectories, the CCP was more receptive to ‘China’ than the Bolsheviks were to ‘Russia’, and this led to two distinctive ways of reorganizing empires into nation-states.