In this paper, the conceptual framework of IBS(Intelligent Building Systems) is redefined, and we propose two ANP(Analytic Network Process) models for ranking IBS. Traditional models have ranked IBS according to technical features or the number of elements in IBS. But, we consider relative functional importance among IBS elements for efficient building operation. According to the structure of interactive-relationship among IBS elements, we present two types of model. The one is Model A that is composed of both hierarchical and network structures. It has $12{ imes}12$ supermatrix consists of interdependent relationship between 6 benefit elements(Productivity, Saving, Safety, Convenience, Pleasantness, Environment Affinity) and 6 IBS elements(Building Operation, Security, Safety, Telecommunication(TC), Office Automation(OA), other elements). Each of 6 IBS elements has subelements in hierarchical structure. The other is Model B that has $25{ imes}25$ supermatrix consists of interdependent relationship between 6 benefit elements and 19 IBS sub elements. Merits and demerits of each model are discussed in detail.