Within an intelligent building, it is expected to offer various intelligent services by recognizing residents along with their lifestyle and needs. One of the key issues for realizing the intelligent building is how to detect the locations of residents, so that it can provide the interactive services based on the identified need and requests. In this work, we develop a wireless pyroelectric sensory system embedded with traditional fire detector, which can be implanted on the ceiling. Both of wireless transmission model and pyroelectric sensor monitoring system can provide the rough information of residents' location respectively. These data can be further improved by reducing the sensory uncertainty through covariance intersection (CI) data fusion method. Pyroelectric localization system suffers from multi target tracking and wireless pyroelectric sensor system works this issue. With the location obtained from wireless pyroelectric sensor system, intelligent building can offer suitable services.