Nutrient monitoring in the marine environment is essential for protecting marine ecosystems. Monitoring nutrient salts in the marine environment is essential for the protection of marine ecosystem. However, traditional monitoring methods have the disadvantages of complicated operation, slow response, and inability to monitor in real time. In order to improve the monitoring efficiency and accuracy, this paper proposes a multi-channel seawater nutrient salt monitoring system based on unmanned shipboard. The system designs the hardware circuit with an STM32F103 microcontroller as the core to realize the real-time and synchronous monitoring of nutrient salts such as nitrate, phosphate, silicate, nitrite, and ammonia nitrogen in seawater. The monitoring system consists of a central control node and five nutrient salts, each independent collection node, the control node and each collection node between the ZigBee wireless communication. Compared with other communication methods, wireless communication is easy to replace and maintain, can reduce the data interruption time, and ensures the validity of data. Experimental results show that the system can efficiently and accurately monitor nutrient salt concentrations in seawater with good monitoring efficiency and accuracy. Compared with the existing technology, this system shows higher data accuracy and better real-time performance, providing an effective technical means for marine environment monitoring.