With the rapid development of cites, urban facilities have rapidly been increasing, and the task of managing them have also become complicated more and more. In this paper, we propose and design an intelligent context awareness system that effectively operates underground facilities in u-City. The suggested system consists of three major steps. The information acquisition step receives alarm information of sensors from the integrated platform. The analysis and inference step analyzes the alarm data and related information and infers the reason why the alarm happens. The information transmission step sends the final results of context awareness to the platform and other related modules. We produced some design products such as data flow diagram, function diagram, etc. We expect that the proposed context awareness system will be embedded in the integrated platform and used for an active management strategy of urban facilities.