Liu Guojun, as a famous library science scholar in China, forged a profound friendship through correspondences with Matsumi Hiromichi, a Japanese scholar whose lifelong project was to explore traditional Chinese history and culture, in the 1950s and 1960s. This article provides an analysis of two exchanged letters between Liu Guojun and Matsumi Hiromichi in 1956, focusing on issues related to the translation and publication of the Japanese version of "The Story of Chinese Books", as well as their hopes for friendly exchanges between the two countries, which has certain value for the study of the exchange of Sino-Japanese library circles in the 1950s. At last，the article called on the scholars pay attention to the study of communication history between China and foreign countries in the field of library science, pay attention to the “outside-turn” of library scholars study and build a library science knowledge system with Chinese characteristics based on China's reality.