The detection of abnormal behaviors is one of the most important issues in the health monitoring system. Computer vision based techniques, usually combined with statistics, are labor-intensive, time-consuming and costly. Moreover, only monitoring but no help functions are provided. To overcome this limitation, this paper presents a ZigBee wireless sensor networks based detection and help system for elderly abnormal behaviors in service robot intelligent space. The main components of the system, including abnormal behaviors detection module, localization of abnormal behaviors, ceiling projector for robot navigation and development of ZigBee wireless sensor networks, are addressed in detail. Finally, we conclude this paper and future research direction is given.