The institutional settings in China, including the land allocation system and the household registration system, lead to a rural-urban labour migration pattern that differs from that in other countries. Individual peasants' labour is often split (typically over different times of the year) into two or more parts as a result of institutional factors. Individuals work both as peasants on the land and as temporary migrant workers in urban areas (or in rural non-agricultural sectors). We examine this issue using province-level panel data. The present study provides a new interpretation of the phenomenon of labour shortages in coastal cities and rising rural migrant wages in China in recent years, and discusses whether the Lewisian turning point has been reached. Under part migration, the rural labour supply to urban areas is smaller than would be the case with full migration of workers to urban areas, so that the Lewisian turning point occurs earlier. This finding has important policy implications for China's future development.