Based on the relevant data of the Beijing Statistical Yearbook and Beijing Education Statistics over the years，this report analyzes and summarizes the development trend and influencing factors of the size of students in the capital’s compulsory education stage and senior high school education stage. The data shows that the size of students in primary education is relatively large and continues to grow，while the size of students in junior high school and senior high school education is small and has a significant downward trend；the size of nonnative students in each education stage shows a consistent downward trend；The Urban function expansion area has become the main distribution area for students in different education stages，and the distribution difference among the functional areas at the junior high school and ordinary senior high school levels shows a weakening trend. The analysis found that the increase of household registration age population，the adjustment of population and education policies，the implementation of relieving Beijing of functions non-essential to its role as China’s capital，and the agglomeration effect of urban high-quality educational resources are the important influencing factors for changes in the size and distribution of the educational population.