The invention provides a method used for constraint fault analysis of instance models and a device thereof. The method comprises the following steps: a plurality of modes are defined for constraint of standard models; the modes comprise navigation modes and logic modes; the presence of blank nodes in constraint appraisal trees generated by the instance models is determined; if the blank nodes are present, the faults of the constraint appraisal trees are analyzed based on the navigation modes; or else, the faults of the constraint appraisal trees are analyzed based on the logic modes. The invention further provides a convenient tool so that connection is established between a model-constraint designer and a model user, thus reducing the use burden of models/constraint and simplifying learning curves as well as helping model users to adjust models.