On-line monitoring of river and lake water quality plays an important role in protecting water resources, preventing water pollution and improving water environment quality. By monitoring water quality changes in real time, we can understand the pollution level, ecological status and overall trend of the water body. Once the monitoring data exceeds the standard range, the system will automatically send an early warning signal to provide early warning information for the environmental management department to take emergency measures. Water quality monitoring can also help us assess the health of aquatic ecosystems and provide data support for water ecological restoration and protection. River and lake monitoring mainly includes pH value, dissolved oxygen, conductivity, turbidity, ammonia nitrogen, blue-green algae, chlorophyll, chemical oxygen demand, oil in water, PAH and so on.