In recent years there has been rapid development of urban rail transit in China. The train driver, as the direct controller of the train, plays an important role in subway operation, and their driving performance directly determines whether the train is safe or not. To explore the relationship between fatigue and unsafe behavior, a simulated driving experiment was designed to record the train driver’s behavior under fatigue and normal state. The changes of operation accuracy and timeliness are used in combination to reflect the train driver’s unsafe behavior. The results show that when the train driver is in a state of fatigue, their operation accuracy is 126% lower than in the normal state. In the operation timeliness index, the time required for the train driver to react and complete the action is 28.13% and 17.7% longer than that in the normal state. It is concluded that fatigued driving can easily lead to unsafe behavior which then leads to potential safety accidents.