This article introduces a ocean buoy data acquisition system based on modular design concept. The proposed system is divided into 3 modules according to the functions of ocean buoy data, i.e. the meteorological safety, hydrology biochemistry and communication. The device can realize continuous acquisition and processing of multiple devices of buoy, as well as real-time two-way communication and other functions. According to the characteristics of different modules, multiplexers and serial port expansion chips are used to realize the interface expansion of the system, which improves the carrying capacity of the system from the hardware. The communication module uses direct memory access technology to realize the forwarding, retransmission and remote control of dual-channel real-time data, realizes the reliable and safe operation of the buoy system at sea, and also improves its human-computer interaction function. The system has been tested in the laboratory and on-site operation experiments at sea to verify its stability, reliability and measurement accuracy.