Wireless sensor networks (WSN) have been considered as a promising system for area surveillance applications. As it moves through a sensor network target tracking has become an increasingly important application in Wireless Sensor Networks. Target detection deals with finding spatial coordinates of a moving object and tracking deals with finding the coordinates and being able to track its movements. Tracking mobile targets using sensor networks is a challenging task. Existing work mostly requires organizing groups of sensor nodes with measurements of a target’s movements or accurate distance measurements from the nodes to the target, and predicting those movements. These are, however, often difficult to accurately achieve in practice, especially in the case of unpredictable environments, sensor faults, etc .In such cases the new tracking framework, called FaceTrack, suits best. FaceTracking employs the nodes of a spatial region surrounding a target, called a face. If a target is detected by a node after a time window, a target is detected by another node. It is assumed to be the same target or single object in FaceTracking method. But it achieves better tracking accuracy and energy efficiency for detecting and tracking single object. This paper proposes a new approach for multi target detection using FaceTracking or polygon tracking method. Simulations are carried out to underline the energy efficiency of the proposed method using NS2.