Abstract: The aim of this paper is to analyze fatigue factors of controllers quantitatively,and study the main rea-sons of controller′s fatigue and related fatigue relieving countermeasures.An index system of fatigue factors of controllers is established based on their personal,environmental,and managerial aspect.The method of Entropy Weight and deci-sion-making and trial evaluation laboratory (DEMATEL)are used together to develop a mathematical model where the entropy weight value is computed through the entropy weight method,and the impact level of indicators determined by DEMATEL method is used to change the entropy weight value.Then combination weight and essential factors leading to controller fatigue are developed.According to DEMATEL method,the causal factors (which affected by others)and the consequent factors (which affect others)are classified.The results show that the combination weight of workload,health status,shifting systems and sleep with higher weight value are the main reasons to controller fatigue,which is 0.204 2, 0.1 52 0,0.146 9 and 0.1 10 3 respectively.Shifting system is the consequent factor,workload,health and sleep status are the causal factors.The entropy and DEMATEL model not only provides a reference for quantitatively analysis of control-ler fatigue,but also points out the direction of implementing fatigue risk management in air traffic control organization.