Lü Yi, courtesy name Jiyang, was a man of Nanyang. His father Lü Chang escorted the former general Liu Yan into Shu, but as the road to the court happened to be cut off, he was never able to return. Lü Yi lost his father as a child, and loved reading books and playing the zither. Records, Shu 9 §39
When Liu Bei pacified Yi Province, he established a Colonel of the Salt Office to manage the profits of salt and iron; later the Colonel Wang Lian requested Lü Yi, Du Qi of Nanyang, Liu Gan of Nanxiang and others, and all were made Commandants of the Bureau of Manufactures. The Biography of Wang Lian also records that Wang Lian selected talented men as his subordinates, and that Lü Yi, Du Qi and Liu Gan all eventually rose to high office. Lü Yi was transferred to be Prefect of Xindu and Prefect of Mianzhu; he devoted himself to pitying and caring for the people, who praised him, and he was foremost among all the cities of the province. Records, Shu 9 §39Records, Shu 11 §10
He was transferred to be Administrator of Baxi. Chancellor Zhuge Liang sent out armies year after year and levied men from the various commanderies, which often could not help one another, but Lü Yi recruited 5,000 soldiers and sent them to Zhuge Liang, and by comforting, admonishing and controlling them he made sure none deserted. He was transferred to be Administrator of Hanzhong, concurrently serving as Supervisor of Agriculture, and kept up the supply of army provisions. Records, Shu 9 §40
After Zhuge Liang died, he was transferred several times and became Administrator of Guanghan and of Shu Commandery. Shu Commandery, where the capital stood, had many households, and after Zhuge Liang's death soldiers deserted and repeatedly assumed one another's names, so frauds and tricks were of more than one kind. On taking office Lü Yi set up measures to prevent and forbid this and guided the people by explanation and exhortation, and within a few years more than ten thousand people who had dropped out of the household registers came forward of their own accord. Records, Shu 9 §40–41
Later he entered the court as Master of Writing, and replaced Dong Yun as Director of the Imperial Secretariat. No business was ever left delayed, and no guests were kept waiting at his gate. Having held offices both in and outside the capital, he kept himself frugal, was modest, quiet and spoke little, and his administration was simple and not burdensome, so he was called upright and capable. However, he applied the law harshly and severely and liked to employ petty officials bound by the letter of the law, so his reputation in high office fell short of that in the commanderies and counties. Records, Shu 9 §41
He died in the 14th year of Yanxi (251). According to the record of Chen Zhi in the same volume, when Lü Yi died, Chen Zhi, as Palace Attendant, acted as Director of the Imperial Secretariat. His son Lü Chen became Prefect of Chengdu in the Jingyao era, and Lü Chen's younger brother Lü Ya was an Internuncio; he was upright, stern and talented in letters, and wrote the Ge Lun (Discourses on Standards) in 15 chapters. Du Qi and Liu Gan were both close friends of Lü Yi and were also praised in their time, but in frugality and observance of the law they did not match Lü Yi. Records, Shu 9 §42–43 · 34
In his assessment Chen Shou, after naming Dong He, Liu Ba, Ma Liang, Chen Zhen and Dong Yun as fine ministers of Shu, said that Lü Yi earned praise when governing a commandery but lost reputation at court, and was also of the class just below Huang Ba and Xue Xuan. Records, Shu 9 §45