Abstract: A new family of object model, i. e. declarative family of object model, was imposed in this paper. The model was defined, geometric and topological structure of this model was presented, semantic of feature was specified by constraints, constraint graph was used to represent features in the model, grammar specification of model was provided.Validation of the model was verified in a instance, and insufficient of traditional procedural-based modeling was overcome, design efficiency of CAl)modeling was developed, and design cost was reduced.

Key words: Family of object, Feature modeling, Geometric constraint, Topological constraint