Abstract: Fatigue driving detection system for EMU drivers based on smart bracelet can alarm the fatigue driving behavior, which is very important to the traffic safety of high-speed railway. This article described the overall design of the system and the function of each module, analyzed the working principle of smart bracelet and the acquisition process of hand acceleration information, based on the analysis of the relationship between the mental state and the hand movement, given the concept of motion coefficient of the hand part, used K-means clustering algorithm for analysis and processing, proposed a fatigue driving detection model for EMU drivers, described the implementation process of the system, built a prototype system in the EMU cab, carried out experiments in the high-speed railway test section. Experimental results showed that the system had higher accuracy in fatigue driving detection