Abstract: To solve the problem that there are many factors influencing the reliability allocation of NC machine tools and some of which are difficult to analyze quantitatively,a comprehensive reliability allocation method is researched using interval analysis,fuzzy comprehensive evaluation and analytic hierarchy process.Many influence factors were considered and endowed with different weight respectively according to the influence degree.In this paper,a reliability allocation model is proposed for NC machine tools,which used interval number instead of real number to express uncertain information.It could make use of the field test information and expert's experience comprehensively.Finally,the application of this method is illustrated with an example,and the results showed that the allocation method is feasible and effective for the reliability allocation of NC machine tools.