Lu Junyi is a fictional character in Water Margin, one of the Four Great Classical Novels of Chinese literature. He ranks 2nd of the 36 Heavenly Spirits of the 108 Liangshan heroes and is nicknamed "Jade Qilin". In the world of published fiction, Lu Junyi is a former student of Zhou Tong.
The novel describes Lu Junyi's appearance as such: nine chi tall, with sparkling eyes and a deity-like appearance. He is a wealthy squire from Daming Prefecture (大名府; in present-day Handan, Hebei). He is also highly skilled in martial arts, especially in the use of the staff. His reputation and charisma earns him the nickname "Jade Qilin", as well as the right to become the second-in-command of the Liangshan outlaws after the Grand Assembly of the 108 Stars of Destiny even though he is one of the last few to join the Liangshan cause.
Song Jiang intends to recruit Lu Junyi after the death of Chao Gai to boost Liangshan's fame and possibly inspire others to join the outlaw band. Wu Yong conjures a scheme to lure Lu Junyi out of Daming Prefecture. He disguises himself as a Taoist priest and pays a visit to Lu Junyi at the latter's residence. He is accompanied by Li Kui, who pretends to be Wu Yong's mute assistant. Wu Yong knows that Lu Junyi is superstitious and he predicts an upcoming disaster for the latter. He says that Lu Junyi will face a violent death within 100 days and his family will die. Lu Junyi believes Wu Yong and asks Wu to help him avoid the disaster. Wu Yong advises Lu Junyi to leave Daming Prefecture and head southeast for beyond 1,000 li. Before leaving, Wu Yong also reads a poem for Lu Junyi, who writes it on a wall in his house. Four Chinese characters that read "Lu Junyi rebels" are hidden in the lines of the poem (see below for details).
When Lu Junyi passes by Liangshan, the outlaws ambush him and Song Jiang speaks to him, requesting that he join Liangshan. Lu Junyi refuses but Song Jiang allows him to leave. When Lu Junyi returns home, he is betrayed by his wife and housekeeper Li Gu, who report to the authorities that Lu is collaborating with outlaws. Lu Junyi is arrested and thrown into prison. Unfortunately for Lu Junyi, Grand Secretary Liang Shijie, the governor of Daming Prefecture, had earlier developed a feud with the Liangshan outlaws after they robbed a convoy of birthday gifts intended for his father-in-law. Lu Junyi is sentenced to exile on Shamen Island (沙門島; present-day Changdao County, Yantai, Shandong). Li Gu bribes the guards escorting Lu Junyi there to kill him along the way. However, Lu Junyi's servant Yan Qing saves him from death, but Lu is later captured again. Yan Qing runs into Shi Xiu and informs him of his master's situation. They storm the execution ground in an attempt to rescue Lu Junyi, who has been sentenced to death, but fail and Shi Xiu is taken captive as well.
Yan Qing escapes to Liangshan and seeks help from the Liangshan outlaws to rescue Lu Junyi and Shi Xiu. Song Jiang feels guilty as he believes that he is responsible for Lu Junyi's plight thus he rallies his fellows to form an army to attack Daming Prefecture and rescue the captives. The imperial court sends another army led by Guan Sheng to attack Liangshan as a diversion to force the Liangshan forces to retreat from Daming Prefecture. Eventually, the outlaws succeed in defeating Guan Sheng and breaking into Daming Prefecture. Lu Junyi and Shi Xiu are rescued and the captured imperial generals, including Guan Sheng, decide to join Liangshan. Lu Junyi returns home after being freed and kills his wife and Li Gu.
Lu Junyi decides to join Liangshan as he has no other choice. He follows the heroes on their campaigns against the Zeng Family Fortress and Dongchang Prefecture. During a battle against the Zeng Family Fortress, Lu Junyi captures Shi Wengong, who is responsible for the death of Liangshan's former chief, Chao Gai. According to Chao Gai's dying wish, Lu Junyi is poised to succeed him as the new chief of Liangshan since he avenged Chao. Lu Junyi feels that he is not qualified to be the chief since he is new to Liangshan and firmly declines the offer. Besides, the majority of the heroes insist that Song Jiang be the new chief since he has made more contributions to Liangshan than any of them. Song Jiang thus becomes the new chief of Liangshan while Lu Junyi becomes the second-in-command.
After the Liangshan outlaws have been granted amnesty by Emperor Huizong, Lu Junyi joins them on their campaigns against the Liao invaders and the rebel forces of Tian Hu, Wang Qing and Fang La. He makes great contributions during the campaigns and survives to return to the imperial court. He is appointed as the governor of Luzhou (廬州; around present-day Hefei, Anhui) by the emperor for his achievements. However, the corrupt officials are dissatisfied with Lu Junyi's fate and want to see him dead. In a ruse by the minister Yang Jian, they summon Lu Junyi back to the capital in the name of the emperor and surreptitiously poison the food and drink given to Lu by the emperor. Due to the pain caused by poisoning, Lu Junyi is unable to ride on horseback during his journey back to Luzhou and has to travel by boat. He misses his step, falls into the water and eventually drowns because he is not a swimmer. His body is later recovered and given a proper burial by the local authorities.
When Wu Yong goes to Lu Junyi's house to predict his fortune, he lies to the latter that he will meet with a disaster within 100 days. Lu Junyi is superstitious and he believes Wu Yong, so he asks Wu for advice on avoiding the calamity. Wu Yong tells him to leave home and travel more than 1,000 li southeast. Before leaving, Wu Yong also reads a poem for Lu Junyi, which Lu writes himself on a wall in his house. The poem is as follows:
The first Chinese character in each of the four lines (in bold) when combined reads "lu jun yi fan" (Chinese: 蘆俊義反; pinyin: lú jùn yì fǎn), which means "Lu Junyi rebels". However, the lu (蘆) in the poem is a homonym of the lu (盧) in Lu Junyi's name. The poem is later used as evidence against Lu Junyi when he is framed for collaborating with outlaws.