Aiming at the complexity of machining center reliability evaluation,a method based on improved entropy weight-TOPSIS-grey correlation was proposed.The subsystem with the highest probability of failure was obtained by using the improved entropy weight for the three indexes:mean time between failures,mean time to first failure and mean time to restoration.The TOPSIS-grey correlation method was used to establish the decision matrix for the subsystem with the highest probability of failure,the positive ideal solution and the negative ideal solution were calculated,the relative closeness degree of grey correlation was obtained,and finally the ranking of the importance degree of each fault mode was acquired.Compared with the traditional frequency method,the results show that it is more reasonable to use the improved entropy weight and TOPSIS-grey correlation method to evaluate the reliability of machining center.