This paper shows telemetry system to monitor muddy river flow by video image processing. The system is constructed by two parts; Local and Host system. Local system placed at near river is the measurement system of river flow. Host system is the monitoring system at remote place from river. The characteristic of river flow is evaluated by the flow speed and direction in each small block distinguished evenly on a video frame. By the evaluation, water behavior and dangerous area will be distinguished. Aim of this study is to observe safely, to discover the dangerous area and to inform local or national government and alarm people.