Abstract: Feature-based method is the focus of heterogeneous CAD model exchange. In order to keep the consistency of design intent in heterogeneous CAD model exchange, a constraint conversion method was proposed. Firstly, Feature transformation ways were given to support the correct conversion of constraint. Secondly, the geometric certificate was improved to identify geometric elements and geometric element is the acting object of constraint. Thirdly, the constraint conversion method on level of feature was proposed corresponding to different types of feature and the global transformation method of constraint during heterogeneous CAD models exchanging. Finally, a transformation case of part model from CATIA to UG shows that the approach proposed above is effective.