An accurate understanding of the changes in the school-age population is essential for the effective allocation of compulsory education resources. Material, human, and financial resources are crucial components of the resources required for compulsory education. By forecasting the size and rural–urban distribution of the school-aged population during the compulsory education phase based on the 7th National Population Census data, we can conduct an in-depth study to plan the allocation of these resources. The research results are as follows: In urban areas, the number of students requiring admission to primary and lower secondary schools will peak rapidly but then decline sharply after the peak. In rural areas, the number will continue to decrease. In response to these changes, lower secondary schools will face short-term pressure to accommodate an increasing number of students, but the overall demand for compulsory education will continue to shrink. Rural areas urgently need to address issues such as the utilization of empty school buildings and the reuse of material resources. The allocation of teacher resources will face alternating period of shortage and surplus, with a specific structural shortage of music, sports, and art teachers. Additionally, the pressure on public finances to meet school funding needs will continue until the peak of the school-age population is reached. To address the changing school-age population and the need for high-quality educational development, the government needs to plan and allocate educational resources in advance, with a focus on adequacy, equity, and efficiency, to ensure the achievement of educational modernization.