Mobile machines displayed many problems in environment of Mobile data nin. So each Mobile companies made each emulator and API. As the result, CP Company had to support not special integrated service but each one tested and developed to each emulator for all Mobile companies. Those kinds of problems had caused the necessity of Mobile contents conversion system. In this theses, it presents the way to reduce huge expense by embodying contents conversion system that can convert each different contents to suitable one at each company and either how to not only improve reciprocal processing ability of data, but only to reduce expenses and efforts for development of public data and softness of program by using XML documents in environment of Mobile data service.