 Inspired by Chen Di, who had demonstrated that the Old Chinese has its own phonological system, Gu divided the words of Old Chinese into 10 rhyme groups, the first one to do so.His positivist approach to a variety of disciplines, and his criticism of Neo-Confucianism had a huge influence on later scholars.His works include "Yinxue Wushu" (), "Ri Zhi Lu" () and "Zhao Yu Zhi" ().