Aiming at the shortcoming of traditional integration, this paper researches the multi-system integration technology of small arms research institute based on ESB. First, it analyses the present situation and requirement of digital construction of small arms research institute, describes the selection of the integration methods between digital systems, and proposes the integrated information relationship between digital systems based on the actual requirements of development and management operations, identifies the source of all types’ data. On this basis, the overall integrated planning of the digital system based on ESB is proposed, the structural relationship between data is clarified, the realization scheme of multi-system integration technology based on ESB is detailed designed, including the realization scheme of digital system integration technology, and the realization scheme of single sign-on and unified centralized processing of to-do transactions in digital system based on portal system. Through the technical proposal, the data sharing and effective transfer between different systems is realized, the mesh interface problem caused by point-to-point integration is eliminated, and the cost of integrated development and maintenance of digital system is reduced.