Sihui's 2021 population is now estimated at 618,859. In 1950, the population of Sihui was 3,118. Sihui has grown by 27,779 since 2015, which represents a 4.70% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Sihui, which typically includes Sihui's population in addition to adjacent suburban areas.