Because of the requirement of software reuses determined by adaptability, the component model has become an ideal choice of software architecture in research of pervasive computing. To abstract the characteristics of components precisely in the pervasive computing-oriented environments, as a part of research in a self-adaptive pervasive computing-oriented software platform UbiStar, a component definition language UCDL is presented. The design of UCDL refers to the manner of using IDL3 and CIDL to abstract the characteristics of components in CORBA Component Model. In the end, an example of the application of UCDL is also presented.