In this paper, the concept of object assembling and automatic maintenance of its association semantics are discussed. After presenting the model of object assembling, the mechanism of its language description and implementation are described, which is based on object hook interfaces, rather than the ordinary object interfaces, and through which the domain-oriented dynamic manipulation of object association and automatic maintenance of association semantics are achieved. This has greatly enhanced the description ability and the dlexibility,and decreased the complexity of object association.As a mechanism of objects and object relation description and manipulation,it gives a new idea to realize software IC,and its usage,formalization and standardization will provide a new technique foe industrialized production of the software.