This paper deals with technology relevance analysis, which measures technological dependency between needs technology and its component technology as well as between needs technologies. The two-round survey was carried out: In the first round, a wide range of needs technologies in construction and building industry were identified and classified to meet a variety of social needs which were anticipated in the near future of Korea. In the second, relevance between needs technology and its component technologies was checked by some 120 experts. Based on the survey results, the individual relevances among needs technologies were computed. Finally the ranking of needs technologies in construction industry was set according to the degree of technology relevance. This relevance is to be used as one of criteria for the selection of national R&D projects which the Ministry of Construction and Transportation plans to promote in the next five years.