Abstract: The architecture of the repository system metadata is hierarchical, multi-layer, dynamically changed and complicated; the prevailing repository system specifications provide insufficiently support for validating well-formedness constraints, so how to check well-formedness constraints for MOF (meta object facility) metadata repository systems becomes a difficult problem. This paper presents an approach which can reasoning on the well-formedness constraints in the different layers, thus the operations that may violate the constraints can be determined automatically. Firstly, a group of inner activities which are more accurate and adaptable than establishment activities provided by MOF are proposed. We define the correspondence between inner activities and establishment activities. Then we research how to reasoning on the constraints directly so that the incoherent inner activities can be detected. At last, we research how to deduce potentially incoherent operations by determining the establishment activities that potentially violate the constraints and testing whether these activities are included in the operations. Our approach can improve the efficiency of well-formedness constraint checking because the precise set of constraints that will be violated by operations can be reduced in the actual checking process. In addition, our method also helps to the constraint design process since we can discard the constraint if we find it can never be violated by any operations.