東晉史家習鑿齒的史著《漢晉春秋》、《襄陽記》兩本著作雖然合計於裴松之《三國志注》徵引的數目中僅排名第八。在一百五十七種史籍中遠不及曹魏．魚豢《魏略》、《典略》與王沈《魏書》、孫吳．韋昭《吳書》等著作。但由於習鑿齒在唐代史家所撰《晉書》中備受推崇，其人格也爍耀千古，不像王沈的行徑頻遭非議，也不像魚豢人微言輕、名不列經傳，更不像韋昭在傳統三國史中向來置身在曹魏、蜀漢爭霸的舞臺漩渦之外。故習氏之作的重要性不應以量次計，尤以其在一片擁曹抑劉的潮流中，獨標仁義王道之師，力舉蜀漢大纛，對爾後南宋．朱熹《通鑑綱目》以蜀漢爲正統的史觀遙啓其端，進而對說部《三國志演義》的敘述角度及諸多重要情節產生極重要而深遠的影響。是以本文即擬就習氏如何透過對諸葛亮神話的建構逐步架築其蜀漢正統論的歷史體系，進行描述與解析，並試圖據此標示習氏在三國史研究中的關鍵地位。

Among the 157 historical works cited in Pei Song-Zhi's commentary on the "Records of the Three Kingdoms", Eastern Jin historian Xi Zao-Chi's two historical works "Spring and Autumn Annals of the Han and Jin Dynasties" and the "Sages in Xiangyang" only rank as the eighth most frequently cited works. This rank is far lower than that of Yu Huan's "Brief Account of the Wei Dynasty" and "Brief Account of the History Records", Wang Chen's "Book of Wei", and Wei Zhao's "Book of Wu". Nonetheless, the cited frequency does not represent the importance of Xi's works, because Xi is heavily praised in the Book of Jin and long remembered as a person with a dignified personality. He is very different from Wan Chen, who is often criticized for his behaviors; Yu Huan, whose personality and words are scarcely mentioned in the history; and Wei Zhao, who has always been outside of the struggles between Cao Wei and Shu Han in the history of the Three Kingdoms period. Instead of following the prevailing tendency to praise Cao and repress Liu, Xi strongly praises Shu Han and stands for virtue and benevolence in his works. His idea becomes the precursor of the historical perspective that regards Shu Han as the legitimate regime of the Three Kingdoms, which greatly influences Zhu Xi’s "Outlines of the Comprehensive Mirror of Aid in Government" as well as the narrative angle and key plots of the "Romance of the Three Kingdoms". With the above concerns, the article describes and analyzes how Xi develops the historical structure that maintains the legitimacy of Shu Han by constructing the myth of Zhuge Liang, and thus proclaims Xi's importance in the studies of the Three Kingdoms history.