UML language provides a promising way to overcome software system complexity. In particular, UML is a unified language that handles different aspects of software modeling. However, its features are not independent which is the source of numerous inconsistencies. Present consistency checking techniques are limited either to certain UML features or to certain kinds of inconsistencies. Our study aims at developing a unified checker which is able to handle all inconsistencies on all UML features. This paper develops the translation from UML models to CLP (Constraint Logic Programming) clauses taking advantage of meta-modeling techniques. CLP is also used to express consistency rules. Then CLP solver can automatically detect inconsistencies.