Zixue Daquan (《字學大全》) is a rhyme book and character book compiled and published by Wang Sanpin (王三聘) in the Ming Dynasty from 43 to 45 years of Jiajing. It contains a large number of difficult glyphs that are not collected in today’s large dictionaries or whose source is unknown. This paper selects 15 difficult glyphs for textual research, including clarifies the correct characters as well as find out the trajectory and the reasons of the standardized form of Chinese character into the vulgar characters, in order to enrich the modern Chinese character font library. At the same time, it provides a reference for the study of difficult characters and the revision and improvement of today’s large-scale dictionaries.