San Guo Zhi, a famous history works, is being studied by more and more researchers because of its realistic, reliable and rich data, esp. its value in language. In the process of being handed down to the next generation, there produced many variants, which are not still emphasized until today. This article tries to set up a new dimension of studying variants based on Chinese philology, that is, to study variants from the angle of Chinese language history. The whole thesis is divided into six parts: The first part expounds the study significance, the history and present situation. The second part argue about the definition of variants. The third, fourth, fifth and sixth parts discuss respectively the significance of studying variants to Chinese language study from the aspects of vocabulary, grammar and rhymes. The seventh part is conclusion.