To solve the traditional water quality detection using ZigBee, GPRS, and other communication technologies having limited coverage distance, high power consumption, high cost, and complex deployment problems, according to the water quality testing real-time monitoring requirements, an NB-IoT-based water quality monitoring system platform is designed. The system uses the "end-tube-cloud" of the Internet of things mode, through the temperature, pH, dissolved oxygen, and other sensors to collect water quality parameters. M5310-A module will receive the sensor data uploaded to the OneNET cloud platform to achieve the remote transmission of water quality information and display functions, while the user can be in the application terminal real-time monitoring and directly read the water quality parameters of the measured waters. The system effectively improves the efficiency and modernization of water quality monitoring work, with good application prospects and economic benefits.