Natural draft cooling towers, as a crucial structure in the power generation industry, are susceptible to corrosive environments that accelerate the corrosion of internal steel reinforcement, especially in coastal areas. The aging of cooling towers, along with issues such as reinforcement corrosion and concrete spalling, can severely endanger structural integrity and seismic performance and raise the risk of disastrous earthquake failures. Therefore, a comprehensive analysis of seismic fragility considering corrosion is needed. A reverse modeling approach was employed to obtain damage information of an existing cooling towers subjected to reinforcement corrosion by combining unmanned aerial vehicle (UAV) and ground-based laser scanning technologies. The spatial-related damage features are extracted from UAV tilt photography with the method of multiscale segmentation and object-oriented classification. Then, the point cloud coordinates of the cooling tower were transformed using the Mercator projection algorithm and edge information such as spalling concrete and cracks in the captured image were detected and enhanced using the Canny edge detection algorithm. Reinforcement corrosion areas were located and identified based on computer visions, and spatial non-uniform of reinforcement corrosion was observed on the cooling tower. On the whole, the outside surface of the cooling tower facing coastal line and the top ring showed a more severe corrosion degree. The developed numerical model based on reverse modeling was utilized to analyze the failure pattern and dynamic response under earthquake attack, and seismic fragility analysis was conducted using different ground motions. Compared with the original cooling tower without reinforcement corrosion, the corroded cooling tower exhibits accelerated failure, and its overall failure probability rises significantly. The variability affected by different ground motions is significant. The corroded cooling tower is differentially sensitive to different ground motions and may be prone to rapid failure under specific ground motions when affected by corrosion.