The purpose of this paper is to develop a novel assembly information model, hierarchical assembly pair (HAP), as the basis of rapid assembly modeling, which aims to refine the current product-modeling paradigm and forms an advanced product-modeling framework. Apart from the geometry level, this model expresses the designer’s assembly design intent (ADI) at the feature level and part level, thus forming three sub models. Based on the model, some new technologies in the field of CAD can be integrated to promote the ADI’s automatic transformation at different levels and efficient transmission between structure-similar part models. Moreover, as the carrier of ADI, HAP can be embedded into the part models at part modeling stage and instantiated to assemble the parts at assembly modeling stage, thus reducing numerous tedious and error-prone operations such as picking up geometry elements and inputting constraint commands. The example of machine vice proves the validity of the model.