During these years, the development of the HL7 standard is raising fast. There are more and more researchers taking notice of the clinical document architecture (CDA). Because it is sometimes hard to exchange medical messages actually, we try to find a solution. In this paper we advance a new usage of the CDA Portable CDA. The Portable CDA is basically a HL7 V3 RIM architecture and CDA R2 standard. First we will introduce the relative terminologies, included HL7 V3 RIM and CDA R2. Then we illustrate why we need the Portable CDA and what kinds of functions should the Portable CDA have. The architecture of the Portable CDA will also be mentioned. Finally, we discuss the future work of our design. There are still a lot of things needed to be done.