This paper proposes a street light warning system based on Internet of Things (IoT) technology, which uses cameras to detect moving targets such as vehicles and pedestrians around the system and adjust the brightness of street lights according to road conditions to reduce unnecessary power waste. The system has a mature self-fault detection mechanism and is equipped with a wireless communication device for data exchange and timely communication with the host computer terminal. The intelligent street lamp system in this paper can be used to reduce the occurrence of pedestrian and vehicle accidents at intersections, and at the same time reduce the consumption of manpower and material resources for street lamp troubleshooting, to achieve energy conservation and emission reduction.