Population projections in China are made using two methods: one based on total population growth rate and the other on births, deaths, and migration. The country uses a unique fertility rate method to calculate future population, considering factors like family planning standards. These projections help in controlling population growth by estimating the impact of current policies. Short-term projections (5-10 years) are accurate and useful for planning, while long-term projections (30-50 years) show trends but need periodic updates. Understanding marriage ages, birth intervals, and family size is crucial for accurate projections. Migration also plays a role in population changes, especially in urban and industrial areas. The main goal of population projection is to predict future population trends based on current socio-economic conditions and policies.