Under the background of energy internet, the accuracy of state parameters sensing for power equipment condition assessment is required to be higher and higher. To grasp the health status of overage transmission tower structures in real time, this paper built a wireless sensor network-based structural health status monitoring system for 4 transmission towers currently in operation in Linyi, Shandong Province. The control parts and damage-sensitive parts of the tower structures were determined by finite-element analysis. The working stress, deformation, and vibration of the structures, foundation displacement and settlement, and other information about the health status of the structures were thereby monitored online in real time. The results show that the proposed monitoring system operates well and the monitored data on the strain, vibration, and settlement fluctuate steadily. Moreover, the health status of the tower structures exhibits no abnormality. In this way, the proposed system effectively guarantees the safe and stable operation of the transmission towers.