In the field of electronic engineering, microcontroller control technology has always been a hot research topic. This paper delves into the design of a colorful running light based on a microcontroller, aiming to achieve more dazzling and variable running light effects through innovative circuit and program design. The design involves various aspects such as the microcontroller's hardware selection, circuit connection, and program algorithms. With carefully designed algorithms, the color transition of the running light is smoother and more natural, giving a visually pleasing experience. At the same time, we will provide detailed explanations of the implementation principles of each running light effect, enabling readers to have a deeper understanding of microcontroller-controlled running lights. It is worth noting that the running lights designed in this paper go beyond simple cyclic changes and include some innovative designs, making the entire light effect more unique. Through this research, we hope to provide new ideas and methods for the application of microcontroller control technology.