The u-City is next generation IT-City which is to enhance the quality of life and convenience of life base on merger up-to-date communication infrastructure with u-IT services. To realize u-City, intelligent building is built for citizens to make a space of comfortable life. The intelligent building is possible to be constructed by communication infrastructure for various U-services. This paper mentions the ranges of communication infrastructure and shows how to construct it each range through regulation, law and technical. Lastly, the topics are suggested to build successfully u-City constructions in Korea.