科技日新月異，近年來無線網路的蓬勃發展，延伸出許多不同型態的無線網路類型，其中無線感測網路(Wireless Sensor Networks, WSNs)更是一個熱門的研究議題。無線感測網路是由一群分散式的感測節點所組成，每一個感測器皆具有運算、感測之功能，可以針對不同的應用去感測不同的環境，並將這些感測到的資料回傳到資料收集中心。然而在傳輸過程中如何有效的將大量的資料作聚集的處理，降低感測節點電力上的消耗，是很重要的研究之一。 本論文利用的是取重心的方式，先建出一條樹狀的路徑，再做資料聚集，此機制還可以解決熱點（Hot spot）問題，達到整體網路電量負載平衡，改善整體網路時間，延長網路壽命。 The advancement of technology changes with each day. In recent years, it extends many different types of wireless network. Wireless sensor networks become a hot issue in research. Wireless sensor networks are composed of multiple sensor nodes that are randomly deployed. Each sensor node has sensing and computing capability to sense different environments according to different applications and transmit these data to sink. However, how to reduce energy consumption in the transmission process is important research. In this thesis, we propose a Tree-based Data Aggregation Mechanism using Center of Gravity (TDCoG). Initially, it builds transmission paths of tree structure, and then does data aggregation. This mechanism may solve the hot spot problem and achieve the effect that loading balancing of energy and extending the lifetime of the network.