In order to improve the production efficiency and quality of automatic production line and realize the visualization of real-time status data of production equipment, the production line data system of an ammunition assembly machine is built. STM32F103 is used as the main control chip of the lower computer, which undertakes the task of collecting data and controlling, and transmits the collected data to the client of the industrial computer through RS485. At the same time, the lower computer packs the periodic data and uploads it to the message queuing telemetry transport (MQTT) server implemented by Java and PostgreSQL database to realize the visual display of the data. The application results show that the data transmitted by the system has high accuracy and low delay, and the data display is intuitive, which can provide a reference scheme for the visualization development of automatic production line system.