The interval non-probabilistic reliability analysis method may lead to conservative design under some conditions, and increase the project cost. To resolve the issue related to the applicability of interval non-probabilistic reliability method, the probability theory and Monte Carlo method are introduced, and the evaluation index for applicability is determined. Then the study method is proposed for application of the interval non-probabilistic reliability analysis method. Based on the analysis of practical problems, the applicability problem of interval non-probabilistic reliability analysis method is discussed, and the applicability of interval non-probabilistic reliability analysis method is investigated for different changing ranges of interval independent variables, number of interval independent variables and function types. The results show that when the changing range is relatively large and the number of interval independent variables is large, the applicability for interval non-probabilistic reliability analysis method is lacking. This study can provide a reference for the application of interval non-probabilistic reliability analysis methods.