After attending the national conference of the Chinese Mathematical Society in Wuhan, which ended on October 27, he hurried back to Baotou by train in order not to miss his classes. After stopping briefly at Beijing for the libraries, he arrived home at about 6 in the evening of Sunday, October 30, 1983. He told his wife joyfully about the praises he received in the last few months and his future research plan. At about 1 am that night, he suffered from a sudden heart attack in his sleep and died. Although his wife was a doctor, she did not have any equipment to save him, not even a telephone at home to call for help. He was survived by his wife Zhang Shuqin () and two daughters. Only two days before his death, his middle school received a letter from the President of University of Toronto David Strangway written on September 30. In the letter, he asked the school principal for permission to transfer Lu to a university for the development of Chinese mathematics. On November 23, David Strangway sent a letter of condolences to Lu's middle school and family, in which he said that people would greatly miss "Prof. Lu Jiaxi" for his knowledge and contributions. In January 1984, an editor of Mathematical Reviews sent Lu an invitation letter to be a reviewer, not knowing of his death. After his death, the Inner Mongolia government helped his family repay their debts and honored him for his achievements. On the first anniversary of his death, a memorial gathering was held by the government officials at Baotou First Workers' Cultural Palace, and the Chairman of the Autonomous Region issued a document titled "Learn from Comrade Lu Jiaxi" (). He was given Special Class Award in the first Inner Mongolia Autonomous Region Science and Technology Progress Award in 1985. An investigation on his research was carried out by a number of Chinese mathematicians. Although his 1961 and 1963 papers were lost, they found the manuscript of his 1965 paper and confirmed that it was the first paper to solve the generalized Kirkman's schoolgirl problem completely. In fact, according to Zhu Lie, it contained an asymptotically stronger result than that in the paper by Ray-Chaudhuri and Wilson. Eric Mendelsohn praised Lu's large set theorem as one of the most significant achievements in the field in the past 20 years. He wrote an