In a Modern communication network, data exchange become a complex problem because there usually exists a various data formats due to the diversity and complexity of communication devices. In this paper, a communication middleware with unified data transmission interface is introduced, which acts as the abstract communication layer in the heterogeneous distributed private communication network. Devices within the network only need to interact with the middleware, instead of directly communicate with each other by various protocols and interfaces, which can reduce the complexity and diversity of the heterogeneous network. This article describes the structure and features of the middleware, and analyses the use of “buffer pool” in message sending and receiving process. The applications of this middleware can reduce the complexity of heterogeneous network interoperation, and improve communication efficiency.