In view of the parameter acquisition problem in the navigation condition monitoring and trial performance evaluation test of Unmanned Surface Vessel (USV), a USV navigation condition monitoring system is designed. Based on the 3-layer architecture of Internet of Things (IoT), a small size and low power consumption monitoring scheme is designed. The multi-source sensors and STM32 microcontroller are used as the sensing layer, the Long Range Radio (LoRa) gateway and LoRa terminal are used as the remote data transmission channel, Transmission Control Protocol (TCP) is used as the remote data transmission protocol, the cloud platform is used as the system application layer, and the data collection, transmission, and application functions are realized. Based on the requirements of monitoring system, the threshold value is set in the application layer to realize the navigation condition warning function. The test results of system function and performance show that the rolling and pitching accuracy is ±0.02° RMS, the wind speed is (0.2±0.03) m/s, the wind direction is ±2.5°, all the monitoring parameters meet the requirements, and the packet loss rate is 1.5% when the communication distance is less than 1.4 km, which is about 22% lower than the traditional method. The system can provide technical support for further improving the USV navigation condition monitoring.