Abstract
The Law of effective building and operation for the information systems took effect at Dec. 2005. Every government and public agency have to build own enterprise architecture(EA), sometimes it's called the Information Technology Architecture(ITA), by this law. The Ministry of National Defense(MND) built the enterprise architecture(EA) during 2006. 12$\sim$2007. 11 by this law too. We knew the specific characters of the public sector thru the EA project. The public sector is less active than commercial sector and most members of the public sector are just looking on the project as a spectator. So the most of key for the success of EA is how to catch the Sponsorship and Participation of members. In this paper we propose the effective building methodology for the Enterprise Architecture of public agency applying the MND-EA. The other governments and public agencies can build own the EA easily by the proposed methodology.