Haimen's 2025 population is now estimated at 714,521. In 1950, the population of Haimen was 3,118. Haimen has grown by 15,385 in the last year, which represents a 2.2% 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 Haimen, which typically includes Haimen's population in addition to adjacent suburban areas.