Reinforcement recovery and reinforcement is an important work and long-term task in the field of hydraulic structure, which are of significance to ensure the safety service of the project, to develop the project benefit, and to extend the service period of the project. The cost calculation and decision making model of hydraulic structure maintenance and reinforcement and its algorithm are established under the premise of ensuring structure safety and reliability, with the consideration of the deterioration characteristics of structural performance and the introduction of life cycle cost theory from the objective of optimizing the whole life cycle cost in engineering. The proposed method is applied to a hydraulic structure, and the concrete maintenance plans during the whole life cycle are calculated and formulated. The result shows that the models and methods in this paper can provide some scientific basis for the maintenance and reinforcement strategies of hydraulic structures in the whole life cycle.