Abstract: In order to meet the requirements of ecological conservation for the effectiveness and stability of water quality monitoring on large watershed water bodies with poor signal coverage of operators and inconvenient communication infrastructure, an IoT water quality monitoring system is designed and implemented based on Niagara IoT middleware and LoRa low-power WAN communication technology, including sensor data acquisition and processing, edge computing, LoRa communication, BP artificial neural network and data visualization. The system supported the rapid networking deployment of new nodes, and its reliability and scalability were verified by the operational results in the Taihu Xiaoxiawan Ecological Conservation Experimental Zone.