以低出生率背景下日本义务教育小班化为研究对象，系统考察其政策演进的内在逻辑与实践特征。伴随少子化加剧导致学龄人口锐减，日本及时谋划应对，并注意顶层设计，加强部门协调，因地制宜设置班额标准，并对其进行动态调整。实践表明，小班化改革显著提升了学生的学业，学生出勤率得以改善，师生互动得以增加。日本经验还揭示了在小班化教育改革过程中要注意的事项，如必须得到国家的财政支持，需要得到法规保障，小班化的规模要适度，小班化要提升教育质量，还须配套理念更新、师资培训、课程改革、评价改革等系列工程。

Taking the small-class education reform in Japanese compulsory schooling under the context of low birth rates as its research object, this study systematically examines the internal logic and practical characteristics of its policy evolution. As population aging and declining birth rates have led to a sharp decrease in the school-age population, Japan has proactively planned its response by emphasizing top-level design, strengthening inter-departmental coordination, setting class-size standards based on local conditions, and implementing dynamic adjustments. Empirical evidence indicates that the small-class reform has significantly improved students’ academic performance, boosted attendance rates, and enhanced teacher–student interaction. The Japanese experience further reveals key considerations for implementing such reforms: they must be underpinned by national financial support and legal safeguards; class sizes must be appropriately scaled; quality improvement should be the core objective; and the process must be supported by a series of coordinated initiatives, including conceptual renewal, teacher training, curriculum reform, and evaluation system innovation.