Smart Cloud Internet of Things is a public-oriented Internet of Things access platform, committed to providing convenient access, storage and display for network enthusiasts and developers, and also providing more Internet of Things applications for developers. This paper proposes an Internet-based river pollution monitoring and treatment technology. It is mainly composed of hardware detection system, electronic patrol inspection system and remote video real-time monitoring system. The hardware test part involved in the invention includes a processing and control unit, a module, a water quality sensing and transmission unit, and an ultrasonic cleaning element. The system is composed of water temperature probe, dissolved oxygen probe, conductivity probe, turbidity probe, flow rate probe, etc. The power conversion device provides all the power. Its advantages are that users can monitor the water quality of the river in real time, transmit images in real time, observe the river in real time, and display the river condition intuitively. Through the analysis of experimental data, this paper evaluates the evaluation value of various indicators of sewage according to the online detection of chemical oxygen demand (COD). It is easier to use COD online detection. Through the satisfaction analysis of COD online detection and manual detection efficiency, it is found that the efficiency of COD online detection is 18.87% higher than that of manual detection.