Hu Pu’an (1878–1947) compiled the Ziyuanxue jiangyi (Course Materials on Theories of Chinese Characters) for the Chinese Language Department of the Commercial Press Correspondence School. This textbook was specifically designed for correspondence students with an educational level equivalent to primary school graduates. Focusing on the Six Principles (Liushu) of Chinese character formation, it employed numbered headings and clear examples, illustrating an endeavor to popularize knowledge of Chinese character studies. This paper utilizes Ziyuanxue jiangyi as the core text and compares it with Hu’s Liushu qianshuo (A Brief Introduction to the Six Principles) and Wenzixue ABC (The ABC of Chinese Grammatology). It explores how he modified the language style and educational content to suit the audience, analyzing the variations in format and knowledge translation strategies across lecture-oriented, popularizationoriented, and correspondence-oriented teaching materials. This paper examines Hu Pu’an’s “scaffolded explanation” process, transitioning from academic to popular formats and subsequently to correspondence education. The “scaffolded” approach refers to content stratification based on varying levels of difficulty and embodies a structured, guided, and systematic knowledge translation. This includes simplifying terminology, incorporating life-like examples, and reorganizing the teaching material structure. Although Ziyuanxue jiangyi is brief and has not been a mainstream focus in academia, this study reveals it as a unique case in the evolution of Chinese language education and Chinese character textbooks during the early Republic of China through textual analysis. Hu’s translation practice fills the gap at the intersection of the history of Chinese character teaching materials and the history of correspondence education, offering historical insights for the popularization of contemporary Chinese character education and possessing interdisciplinary significance.