Abstract: The Nanchang Uprising marked the beginning of the Communist Party of China’s independent leadership of armed struggle and the establishment of the people’s army. The spirit of army building that it gave birth to is an important inheritance and concrete manifestation of the great founding spirit. The research on the spirit of army building has been an early concern of the academic community, but its name and connotation have not yet been authoritatively defined, nor has it been officially included in the genealogy of the spirits of the Communist Party of China. Referring to the expression patterns of various spirits in the genealogy of the spirits of the Communist Party of China and combining with the existing research consensus, the connotation of the spirit of army building should include such core elements as “firm belief, following the Party’s command, striving for the people, being a pioneer, being indomitable, and having excellent conduct”. As the 100th anniversary of the Nanchang Uprising approaches, the academic community should seize this important opportunity to deepen theoretical research, reach a consensus, and provide theoretical support for the subsequent confirmation of the name and definition of this spirit by the central authorities.