The evaluation,which is the degree of availability requirements generated by the components of CNC machine tools,must be assessed accurately,for responding the availability requirements of numerical control machine tools accurately and quickly machine tools. The dynamic house of availability(DHOA) model is established through introducing the quality function deployment (QFD) theory,aiming at the characteristic of availability requirements in CNC machine tool and the relationship of self-correlation between the components. Because the correlation coefficient between the user requirements and components in machining center is uncertainty and numerical interval,the calculation of availability requirements importance is realized by combining the interval gray relational analysis model with the DHOA model. Finally,the rationality and availability of the DHOA model is validated by taking a domestic machine center as an example.